Dissertations / Theses on the topic 'Afterglow'
To see the other types of publications on this topic, follow the link: Afterglow.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Afterglow.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Updike, Adria C. "Gamma ray burst afterglow observations." Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1181668208/.
Full text
2
Beier, Matthias. "Transport neutraler angeregter Spezies im Afterglow." [S.l. : s.n.], 1998. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10324547.
Full text
3
Harrison, R. M. "Gamma-ray burst early optical afterglow modelling." Thesis, Liverpool John Moores University, 2014. http://researchonline.ljmu.ac.uk/4425/.
Full textAbstract:
We discuss the evolution of a relativistic outflow responsible for producing the emission associated with GRBs. We investigate how afterglows are produced in the inter- action between the outflow and the ambient medium. Understanding the properties of the outflow from afterglow emission can be coupled with information obtained from the prompt component to constrain the magnetisation of the outflow. We analytically and numerically evaluate the relative strength of the reverse shock emission as the out- flow propagates into either a wind or ISM -type environment. We find that previous estimates of magnetisation based on the relative strength of forward and reverse shock emission had been underestimated by up to a factor of 100. We then apply our revised magnetisation estimate to a sample of 10 GRBs and find that 5 of the 10 events can be described by the ISM model. As recent studies have indicated that the fraction of en- ergy stored in the magnetic fields are small, our findings would suggest that the ejecta is driven by thermal pressure. Finally we consider how inhomogeneities present in the outflow can lead to variations in the very early afterglow. Considering small gradi- ent in the ejecta density profile modifies the rising index of the afterglow and can be equivalent to changing the dimensionless parameter ξ by a factor of 2. Uncertainties in determining the width of the ejecta present difficulties in understanding the distribution of GRBs afterglow rising index.
4
Beier, Matthias [Verfasser]. "Transport neutraler angeregter Spezies im Afterglow / Matthias Beier." Chemnitz : Universitätsbibliothek Chemnitz, 1998. http://d-nb.info/1210712156/34.
Full text
5
Tam, Pak-hin. "A study of the optical afterglows of gamma-ray bursts." Thesis, Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31367677.
Full text
6
Hullinger, Derek. "Early afterglow evolution of x-ray flashes observed by Swift." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3374.
Full textAbstract:
Thesis (Ph. D.) -- University of Maryland, College Park, 2006.Thesis research directed by: Physics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
7
Littlejohns, Owen Madoc. "Modelling the prompt and afterglow emission of gamma-ray bursts." Thesis, University of Leicester, 2013. http://hdl.handle.net/2381/27949.
Full textAbstract:
This thesis studies the broadband behaviour of GRBs by fitting a detailed spectral/temporal model to both the prompt and afterglow hard and soft X-ray emission observed by the Swift satellite. The prompt emission is decomposed into pulses which are fitted individually while the afterglow is modelled using a smoothly varying broad pulse which evolves into a power-law decay at late times. Using this model a comprehensive study of GRB 080310 is presented and followed by similar analyses of GRB 061121, GRB 080810 and GRB 081008. The optical behaviour is found to be inconsistent with the high-energy model: a spectral break between the X-ray and optical band is necessary and for many prompt pulses the self-absorption mechanism is required. The latter three bursts have optical afterglows that are shown to be inconsistent with those fitted to the X-ray regime, peaking earlier in the lower energy bands and requiring a low-energy spectral break. The prompt optical emission seen from GRB 061121 has pulse-like features which match reasonably well with contemporaneous high-energy features, but have longer durations. The same model was used to study the expected evolution of GRB properties when moved to higher redshifts. Using a sample of bright Swift GRBs, the changes in measured duration with redshift were found to be driven by a combination of time dilation, gradual loss of pulse tails and sudden loss of pulses as the flux falls below instrumental sensitivity. A realistic sample of synthetic bursts is produced which, when simulated at high redshift, are found to be significantly longer in duration that the observed high redshift GRBs. Also demonstrated is that several bright bursts seen by Swift could be detected if they occurred at a redshift > 10 encouraging the use of GRBs as probes of the early Universe.
8
Zaninoni, Elena. "Gamma-ray bursts and their X-ray and optical afterglow." Doctoral thesis, Università degli studi di Padova, 2013. http://hdl.handle.net/11577/3422978.
Full textAbstract:
The aim of this PhD thesis is to study and characterize the optical and X-ray emission of the afterglows of gamma-ray bursts (GRBs).
GRBs are the most powerful sources of electromagnetic radiation in the universe, with an isotropic luminosity that can reach values of $10^{54}$ erg/s. The Swift satellite, launched in November 2004, opened a new era for the study and understanding of the phenomenon of GRBs, thanks to the rapid response of its narrow FOV instruments that allows the accurate localization of most GRBs and the more complete coverage of the GRB evolution.
In the first part of my PhD I was involved in a comprehensive statistical analysis of the Swift X-ray light-curves (LCs) of GRBs, carried out in a model-independent way. Our sample is composed of the X-ray LCs of more than 650 GRBs observed by Swift from December 2004 to December 2010. For 437 GRBs the statistics were good enough to allow us to extract a spectrum to convert their count-rate LCs into flux LCs. For GRBs with a known redshift, also rest-frame luminosity LCs in the 0.3-30 keV band were computed. From the fit of these LCs, we obtained the values of the temporal slopes and break times of the continuum of the X-ray emission, since the used fitting procedure automatically discards the positive fluctuations (i.e. flares). Then, we computed the total fluences and energies, those of flares and differentiating between the components of the X-ray LCs. Thanks to this large sample of LCs, we could carry out a homogeneous analysis of GRBs in a common rest frame energy band (0.3-30 keV), investigating the intrinsic time scales and energetics of the different LC phases. In addition, we studied the properties of flares superimposed to the smooth X-ray decay. GRBs are classified as long and short, depending on the duration of the prompt emission (T90>2 s and T90<2 s, respectively); our sample of GRBs allowed us to investigate the possible differencies and similarities between these two classes, for example the nature of long and short GRBs and the emission mechanisms involved. Finally, we examined the possible relation between the X-ray and gamma-ray emission and we found the existence of a universal scaling involving two parameters of the prompt emission and one of the X-ray emission: the isotropic prompt emission energy ($E_{\gamma,iso}$), the peak energy ($E_{pk}$) and the isotropic X-ray energy ($E_{X,iso}$).
The main idea of the project presented above is to study all quantities that characterize the X-ray data and to look for a link between prompt and afterglow emission. During this work, we realized that the optical data were very important for our understanding, adding information to investigate the GRB emission mechanisms and to study the environment properties. Therefore, in the second part of my PhD we carried out a systematic analysis of the optical data available in literature, collecting data from all the available sources. From the collected optical data, we determine the shapes of the optical LCs. Then, we modeled the optical/X-ray spectral energy distribution (SED), we studied the SED parameter distributions and we compared the optical and X-ray LC slopes and shapes. For 20% of GRBs the difference between the optical and X-ray slopes is consistent with 0 or 1/4 within uncertainties (we do not consider here the steep decay phase), but in the majority of cases (80%) the optical and X-ray afterglows show significantly different temporal behaviors. Interestingly, we found an indication that the onset of the forward shock in the optical LCs (initial peaks or shallow phases) could be linked to the presence of the X-ray flares. Indeed when there are X-ray flares the optical LC initial peak or plateau end occurs during the steep decay, instead if there are no X-ray flares or if they occur during the plateau, the optical initial peak or plateau end takes place during the X-ray plateau. This could link the prompt emission with the optical emission. The forward shock model cannot explain all the features of the optical (e.g. bumps, late re-brightenings) and X-ray (e.g. flares, plateaus) LCs. However, the synchrotron model is a viable mechanism for GRBs afterglow emission at late times. Further to the intrinsic spectrum of the afterglow, the SED analysis allows to study the properties of the GRB environment, by quantifying the amount of absorption at optical and X-ray wavelengths. The first is due to dust while the latter is mostly due to metals. Our analysis shows that the gas-to-dust ratios of GRBs are larger than the values calculated for the Milky Way, the Large Magellanic Cloud, and the Small Magellanic Cloud assuming solar abundances.Lo scopo di questa tesi è lo studio e la caratterizzazione dell'emissione X e ottica dei gamma-ray burst (GRB). I GRB sono la sorgente più potente di radiazione elettromagnetica dell'universo, la cui luminosità può raggiungere valori di $10^{54}$ erg/s. Il satellite Swift, lanciato nel novembre del 2004, ha aperto una nuova era per lo studio e la comprensione dei GRB, grazie alla rapida risposta dei suoi strumenti che ha permesso localizzare in modo accurato la maggior parte dei GRB e di ottenere una visione più completa della loro evoluzione. Nella prima parte del mio Dottorato sono stata coinvolta nell'analisi statistica delle curve di luce (CL) osservate nella banda energetica corrispondente ai raggi X del telescopio per i raggi X a bordo del satellite Swift. Questo studio non ha assunto alcun modello teorico per spiegare le osservazioni, ma è stato finalizzato alla raccolta di tutte le possibili informazioni osservative. Il nostro campione è composto dalle CL di più di 650 GRB osservati da Swift tra Dicembre 2004 e Dicembre 2010. Per 437 GRB, grazie alla bontà statistica dei dati, è stato possibile estrarre uno spettro per convertire le loro CL da conteggi a flusso. Per i GRB per cui è stato misurato il redshift, sono state calcolate anche le CL in luminosità nella banda energetica 0.3-30 keV nel sistema di riferimento della sorgente, in modo da approssimare la luminosità bolometrica. Dall'interpolazione dei dati delle CL, abbiamo ottenuto i valori delle pendenze temporali e dei break time, cioè dei tempi in cui la CL cambia la sua pendenza, e abbiamo caratterizzato l'andamento temporale dell'emissione duratura in banda X, escludendo le fluttuazioni (flares) che sono probabilmente dipendenti da meccanismi diversi. Per ogni GRB, sono state calcolate le densità di flusso e le energie corrispondenti all'emissione X totale, dei flares e delle diverse componenti della CL. è stata realizzata un'analisi omogenea dei GRB in una banda energetica comune (0.3-30 keV) nel sistema a riposo della sorgente. I GRB sono classificati come lunghi e corti, in base alla durata dell'emissione iniziale, detta prompt emission (T90>2 s e T90<2 s, rispettivamente); il nostro campione di GRB ci ha permesso di studiare le differenze e le somiglianze di queste queste due classi di GRB. Infine abbiamo identificato una nuova relazione tra l'emissione X e gamma trovando una legge universale che coinvolge due parametri che si riferiscono alla prompt emission e uno che si riferisce all'emissione X: l'energia totale della promp emission ($E_{\gamma,iso}$), l'energia di picco dello spettro integrato nel tempo della prompt emission ($E_{pk}$) e l'energia X ($E_{X,iso}$). L'idea principale del progetto appena discusso è lo studio di tutte le quantità che caratterizzano i dati X e la ricerca di un legame tra l'emissione prompt nei raggi gamma e quella nelle altre bande energetiche, X, ottico e radio, detta afterglow. Durante questo lavoro, ci siamo resi conto della necessità di aggiungere le informazioni che provengono dai dati ottici dei GRB, in modo da studiare in modo più dettagliato i meccanismi di emissione dei GRB e le proprietà dell'ambiente che li circonda. Quindi, nella seconda parte del mio Dottorato ho condotto un mio personale progetto di ricerca, analizzando in modo sistematico i dati ottici disponibili in letteratura. Il primo passo è stato quello di interpolare le CL ottiche, in modo da caratterizzare il loro andamento temporale. Poi abbiamo modellato le distribuzioni di energia spettrale ottica e X (SED) e abbiamo studiato le distribuzioni dei parametri ottenuti da questo studio. Infine abbiamo confrontato l'andamento temporale delle CL ottiche. Per il 20% dei GRB la differenza tra la pendenza ottica e X è consistente con i valori attesi dal modello standard per l'afterglow dei GRB, mentre nella maggior parte dei casi le CL ottiche e X mostrano un andamento temporale diverso. Inoltre, abbiamo trovato un'indicazione che l'inizio della fase di afterglow nelle CL ottiche (che corrisponde nelle CL a picchi iniziali o fasi quasi-costanti) potrebbe essere collegato alla presenza dei flare nei raggi X. Quindi, quando ci sono flares X, il picco iniziale o la fine della fase quasi-costante della curva di luce ottica avvengono durante la fase iniziale della CL X, detta steep decay, invece se non ci sono flare X o se avvengono successivamente allo steep decay, il picco iniziale o la fase quasi-costante della CL ottica si manifestano durante la fase quasi-costante della curva di luce X. Questo potrebbe legare l'emissione prompt con l'ottico. In generale, troviamo che il modello del standard per l'afterglow non può spiegare tutte le caratteristiche delle CL ottiche e X. Comunque, l'emissione di sincrotrone può essere un meccanismo plausibile per spiegare l'emissione dell'afterglow a tempi tardi. L'analisi delle SED ci ha permesso di studiare le proprietà dell'ambiente dei GRB, quantificando la quantità di assorbimento alle lunghezze d'onda ottiche e X. Il primo è dovuto alla polvere invece l'ultimo è dovuto principalmente ai metalli. La nostra analisi ha mostrato che il rapporto tra il gas e la polvere per i GRB è maggiore rispetto ai valori calcolati per la Via Lattea, la Grande Nube di Magellano e la Piccola Nube di Magellano, assumendo abbondanze solari.
9
Mynampati, Venkata N. S. "Simulation of the interaction of argon/helium afterglow with ambient gasses /." Available to subscribers only, 2005. http://proquest.umi.com/pqdweb?did=1083541601&sid=4&Fmt=2&clientId=1509&RQT=309&VName=PQD.
Full text
10
Valan, Vlasta. "Thermal components in the early X-ray afterglow of gamma-ray bursts." Licentiate thesis, KTH, Partikel- och astropartikelfysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217103.
Full textAbstract:
Gamma-ray bursts (GRBs) are still puzzling scientists even 40 years after their discovery. Questions concerning the nature of the progenitors, the connection with supernovae and the origin of the high-energy emission are still lacking clear answers. Today, it is known that there are two populations of GRBs: short and long. It is also known that long GRBs are connected to supernovae (SNe). The emission observed from GRBs can be divided into two phases: the prompt emission and the afterglow. This thesis presents spectral analysis of the early X-ray afterglow of GRBs observed by the {\it Swift} satellite. For the majority of GRBs the early X-ray afterglows are well described by an absorbed power-law model. However, there exists a number of cases where this power-law component fails in fully describing the observed spectra and an additional blackbody component is needed. In the paper at the end of this thesis, a time-resolved spectral analysis of 74 GRBs observed by the X-ray telescope on board {\it Swift} is presented. Each spectrum is fitted with a power-law and a power-law plus blackbody model. The significance of the added thermal component is then assessed using Monte Carlo simulations. Six new cases of GRBs with thermal components in their spectra are presented, alongside three previously reported cases. The results show that a cocoon surrounding the jet is the most likely explanation for the thermal emission observed in the majority of GRBs. In addition, the observed narrow span in radii points to these GRBs being produced in similar environments.QC 20171031
11
Li, Yi, and 李毅. "The thermal afterglow of a pulsar glitch in non-spherical symmetric case." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31215580.
Full text
12
Ionascut, Nedelcescu Anca Marina. "Caractérisation d'une décharge à barrière diélectrique à pression atmosphérique et son afterglow." Thèse, Université de Sherbrooke, 2008. http://savoirs.usherbrooke.ca/handle/11143/1908.
Full textAbstract:
This study presents a detailed optical characterization of a throughflow Atmospheric Pressure Dielectric Barrier Discharge and its afterglow, using emission spectroscopy. The electrical properties such as the power fed into discharge, the energy consumption during one cycle, the dielectric and total capacitance are determined using Lissajous figures. The values of the determined capacities and those theoretically calculated are in agreement. The afterglow length and the effect of the air entrainment at different operating conditions are studied using photographic technique. The non-equilibrium feature of the plasma in the discharge gap and in the afterglow is studied by the analysis of the rotational, vibrational and electronic excitation temperature, using Boltzmann plots. In helium flow, under the same operating conditions, the values determined are: T[indice inférieur r] = 533 « 15 K, T[indice inférieur v] = 2500 « 500 K, T[indice inférieur e] = 2800 « 570 K - in the gap-space, and T[indice inférieur r] = 466 « 10K, T[indice inférieur v] = 2100 « 430K, T[indice inférieur e] = 2600 « 530 K - in the afterglow. In helium flow, spectral line-shape analysis of the He (587.5 nm) and H[bêta] transitions is used to determine the contributions of the Doppler, Stark and Van der Waals effects. An innovative approach to determine the gas temperature T[indice inférieur g], defined as the mean kinetic energy of the gas particles, is given by establishing two parametric equations, one for each transition. These are applied to study the Tîndice inférieur g] variation with the applied voltage, and to determine the accuracy of the use of rotational temperatures as an approximation for T[indice inférieur g]. A linear increase of the gas temperature from 310 K to 460 K with the increase of the applied voltage from 5.8 kV to 10.8 kV is found for both studied lines. The slope of the rotational temperature variation with the applied voltage shows a 35% overestimation of the gas temperature as compared to that obtained from the line shape analysis. On the other hand, no significant variation of the gas temperature with the flow rate could be detected. The upper limit for the electron density at the highest voltage applied is established to be 4 x 10[indice supérieur 12] cm[indice supérieur -3], from the Stark broadening of H[bêta]. Finally, a detailed identification of the active species and their excitation mechanisms, in He and its gas mixtures such as: He-Ar, He-N[indice inférieur 2], He-H[indice inférieur 2]O, He-CH[indice inférieur 4], and He-O[indice inférieur 2], is presented by analyzing the emission spectra in the wavelength interval 300 nm to 900 nm.
13
Li, Yi. "The thermal afterglow of a pulsar glitch in non-spherical symmetric case /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19737051.
Full text
14
Short, Eugene L. "Sequential afterglow processing and non-contact Corona-Kelvin metrology of 4H-SiC." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003102.
Full text
15
Novotný, Oldřich. "Experimental Study of Electron-Ion Recombination Using Storage Ring and Afterglow Techniques." Doctoral thesis, Rennes 1, 2006. http://www.nusl.cz/ntk/nusl-266018.
Full text
16
Short, Eugene L. III. "Sequential Afterglow Processing and Non-Contact Corona-Kelvin Metrology of 4H-SiC." Scholar Commons, 2009. https://scholarcommons.usf.edu/etd/19.
Full textAbstract:
Silicon carbide (SiC) is a wide band-gap semiconductor with advantageous electrical and thermal properties making it attractive for high temperature and power applications. However, difficulties with oxide/SiC structures have posed challenges to the development of practical MOS-type devices. Surface conditioning and oxidation of 4H-SiC were investigated using a novel sequential afterglow processing approach combined with the unique capabilities of non-contact corona-Kelvin metrology. The use of remote plasma assisted thermal oxidation facilitated film growth at low temperature and pressure with the flexibility of sequential in-situ processing options including pre-oxidation surface conditioning. Corona-Kelvin metrology (C-KM) provided a fast, non-destructive method for electrical evaluation of oxide films and semiconductor surfaces. Non-contact C-KM oxide capacitance-voltage characteristics combined with direct measurement of SiC surfaces using C-KM depletion surface barrier monitoring and XPS analysis of surface chemistry were interpreted relating the impact of afterglow conditioning on the surface and its influence on subsequent oxide thin film growth. Afterglow oxide films of thicknesses 50-500 angstroms were fabricated on SiC epi-layers at low growth temperatures in the range 600-850°C, an achievement not possible using conventional atmospheric oxidation techniques. The inclusion of pre-oxidation surface conditioning in forming gas (N2:H2)* afterglow was found to produce an increase in oxide growth rate (10-25%) and a significant improvement in oxide film thickness uniformity. Analysis of depletion voltage transients on conditioned SiC surfaces revealed the highest degree of surface passivation, uniformity, and elimination of sources of charge compensation accomplished by the (N2:H2)* afterglow treatment for 20 min. at 600-700°C compared to other conditioning variations. The state of surface passivation was determined to be very stable and resilient when exposed to a variety of temporal, electrical, and thermal stresses. Surface chemistry analysis by XPS gave evidence of nitrogen incorporation and a reduction of the C/Si ratio achieved by the (N2:H2)* afterglow surface treatment, which was tied to the improvements in passivation, uniformity, and growth rate observed by non-contact C-KM measurements. Collective results were used to suggest a clean, uniform, passivated, Si-enriched surface created by afterglow conditioning of 4H-SiC as a sequential preparation step for subsequent oxidation or dielectric formation processing.
17
Ishikawa, T., D. Hayashi, K. Sasaki, and K. Kadota. "Determination of negative ion density with optical emission spectroscopy in oxygen afterglow plasmas." American Institute of Physics, 1998. http://hdl.handle.net/2237/7091.
Full text
18
Short, Eugene L. "Growth of oxide thin films on 4H- silicon carbide in an afterglow reactor." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001839.
Full text
19
Müller, Meike [Verfasser], and Gregor [Akademischer Betreuer] Morfill. "Characterisation of cold atmospheric plasma afterglow for decontamination / Meike Müller ; Betreuer: Gregor Morfill." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2019. http://d-nb.info/1198112034/34.
Full text
20
Alshammari, Suliman. "Flowing afterglow studies of recombination of electrons with heavy Ions using FALP-MS." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1S013/document.
Full textAbstract:
La recombinaison dissociative (RD) est le processus dans lequel un ion moléculaire positif se recombine avec un électron et se dissocie après en fragments neutres. Parmi les différents types de réactions entre ions moléculaires et électrons, la RD mérite une attention particulière à cause du rôle important qu'elle joue dans les plasmas à basse température et de faible densité, telles que celles rencontrées dans les ionosphères planétaires et les nuages interstellaires. En dépit de l'apparente simplicité de la RD, son étude s'est avéré difficile aussi bien du point de vue expérimental que théorique. Afin d'apporter plus de lumière sur ce processus, la technique de la post-décharge en écoulement a été introduite et a été largement utilisée ces dernières décennies. La présente thèse est dédiée aux études expérimentales de la réaction RD, à l'aide du spectromètre de masse à sonde Langmuir (FALP-MS) en post-décharge en écoulement, à l'Université de Rennes 1, à Rennes, en France. Nous avons étudié la réaction RD à température ambiante a été étudiée pour les ions moléculaires d'acétone ( ) et les cations de diméthylamine cations ( ainsi que les vitesses de réaction des cations de triméthylamine ( cations, et nous avons obtenu des valeurs avec des incertitudes de of ± 30 %. De plus, nous avons étudié l'attachement électronique à la diméthylamine neutre et nous avons trouvé une constante de vitesse de = 4.81 x 10-10 cm3 s-1. Un nouveau système d'injection pour l'anneau de stockage électrostatique de KACST a été conçu et construit dans le laboratoire de l'IPR à Rennes. Le couplage de la source d'ions avec un analyseur de masse quadripolaire et l'utilisation d'un système de vannes pulsées assurant un pompage différentiel entre différentes régions de la ligne d'injection constitue une méthode nouvelle dans le contexte d'un anneau de stockage. Le but final de ce projet est l'étude des réactions à ions lourds tels que les ions moléculaires biologiquesDissociative recombination (DR) is a process in which a positive molecular ion recombines with an electron and subsequently dissociates into neutral fragments. Among the different types of molecular ion-electron reactions DR deserves particular attention due to the important role it plays in low-temperature and low-density plasmas such as those encountered in planetary ionospheres and interstellar clouds. Despite the apparent simplicity of the DR reaction, its investigation has proven to be a difficult task from both experimental and theoretical perspectives. In order to shed more light upon this process the flowing afterglow technique has been introduced and utilised extensively for the last few decades. This thesis is devoted to experimental studies into the DR reaction using the flowing afterglow Langmuir probe mass spectrometer FALP-MS at the University of Rennes 1, in Rennes, France. The DR reaction at room temperature has been investigated for the acetone molecular ions ( ) and dimethylamine cations ( as well as the reaction rates of trimethylamine ( cations, and the obtained values were with uncertainties of ± 30 %. In addition, the electronic attachment to neutral dimethylamine was also studied and the rate constant was determined to be = 4.81 x 10-10 cm3 s-1. A new ion injection system system for the KACST electrostatic storage ring has been designed and built in the IPR laboratory in Rennes. The coupling of an ion source with a quadrupole mass analyzer and the use of a gas pulsing system to maintain the differential pumping between different regions of the injection line, is a novel technique for use with a storage ring. The final goal of this system is to study the reactivity of heavy ions such as biological molecular ions
21
Blessington, Jon C. "Measurements of metastable atom density using energies and densities of energetic "fast" electrons detected in the electron energy distribution function associated with the afterglow plasma produced by a radio frequency inductively coupled plasma helium discharge." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5214.
Full textAbstract:
Thesis (M.S.)--West Virginia University, 2007.Title from document title page. Document formatted into pages; contains v, 36 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 21).
22
Fong, W., R. Margutti, R. Chornock, E. Berger, B. J. Shappee, A. J. Levan, N. R. Tanvir, et al. "THE AFTERGLOW AND EARLY-TYPE HOST GALAXY OF THE SHORT GRB 150101B AT z = 0.1343." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/622673.
Full textAbstract:
We present the discovery of the X-ray and optical afterglows of the short-duration GRB 150101B, pinpointing the event to an early-type host galaxy at z = 0.1343 +/- 0.0030. This makes GRB 150101B the most nearby short gamma-ray burst (GRB) with an early-type host galaxy discovered to date. Fitting the spectral energy distribution of the host galaxy results in an inferred stellar mass of approximate to 7 x 10(10) M-circle dot, stellar population age of approximate to 2-2.5 Gyr, and star formation rate of less than or similar to 0.4M(circle dot) yr(-1). The host of GRB 150101B is one of the largest and most luminous short GRB host galaxies, with a B-band luminosity of approximate to 4.3L(*) and half-light radius of approximate to 8 kpc. GRB 150101B is located at a projected distance of 7.35 +/- 0.07. kpc from its host center and lies on a faint region of its host rest-frame optical light. Its location, combined with the lack of associated supernova, is consistent with an NS-NS/NS-BH merger progenitor. From modeling the evolution of the broadband afterglow, we calculate isotropic-equivalent gamma-ray and kinetic energies of approximate to 1.3 x 10(49) erg and approximate to(6-14) x 10(51) erg, respectively, a circumburst density of approximate to(0.8-4) x 10(-5) cm(-3), and a jet opening angle of greater than or similar to 9 degrees. Using observations extending to approximate to 30 days, we place upper limits of less than or similar to(2-4) x 10(41) erg s(-1) on associated kilonova emission. We compare searches following previous short GRBs to existing kilonova models and demonstrate the difficulty of performing effective kilonova searches from cosmological short GRBs using current ground-based facilities. We show that at the Advanced LIGO/VIRGO horizon distance of 200 Mpc, searches reaching depths of approximate to 23-24 AB. mag are necessary to probe a meaningful range of kilonova models.
23
Lepikhin, Nikita. "Fast energy relaxation in the afterglow of a nanosecond capillary discharge in nitrogen/oxygen mixtures." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX087/document.
Full textAbstract:
L'objectif principal du présent travail était d'étudier, comment la cinétique du plasma change dans les conditions de dépôt d'énergie spécifique élevé dans des champs électriques réduits élevé. La décharge capillaire nanoseconde a été utilisée comme outil expérimental. Les mesures sont effectuées dans l'azote pur et dans les mélanges azote/oxygène. Les paramètres électriques de la décharge sont mesurés: la tension appliquée, le dépôt d'énergie, le champ électrique et le courant électrique. Les spectres de l'émission optique de la décharge sont obtenus. La densité électronique dans les impulsions de décharge est mesurée. La décroissance du plasma est étudiée par les mesures de la densité électronique dans la post‐luminescence de la décharge. Les processus contrôlant la décroissance du plasma sont déterminés. La dépopulation de molécules excitées sur l'exemple de l'azote moléculaire N2(C) est étudié dans des mélanges azote/oxygène. Les processus responsables de la dépopulation des espèces excitées lors de la post‐luminescence de la décharge de nanoseconde à les conditions de dépôt d'énergie spécifique élevé dans des champs électriques réduits élevé sont examinés. La distribution radiale des espèces excitées à différentes compositions de gaz sont étudiée et comparées. L'étude expérimentale et numérique des processus responsables du chauffage rapide du gaz dans l'azote pur et dans les mélanges azote/oxygène dans la post‐luminescence de la décharge capillaire à la nanoseconde sont effectuées. Les particularités du chauffage rapide du gaz aux conditions de la décharge de nanoseconde à de dépôt d'énergie spécifique élevé dans des champs électriques réduits élevé sont étudués. La modification du schéma cinétique actuellement utilisé est proposéeThe main aim of the present work was to investigate, how the plasma kinetics changes at the conditions of high specific energy deposition at high reduced electric fields. The nanosecond capillary discharge was used as an experimental tool. The measurements are performed for pure nitrogen and nitrogen/oxygen mixtures. Electric parameters of the discharge are measured: the applied voltage, the energy deposition, the electric field, and the electric current. The spectra of the optical emission of the discharge are obtained. The electron density in the discharge pulses is measured. The plasma decay is studied by the measurements of the electron density in the afterglow of the discharge as well. The processes controlling the plasma decay are determined. Depopulation of excited molecules on the example of N2(C) state of molecular nitrogen is studied in nitrogen/oxygen mixtures. The processes responsible for depopulation of excited species in the afterglow of the nanosecond discharge at high specific deposited energy at high reduced electric field are discussed. The radial distributions of the excited species at different gas compositions are investigated and compared. The experimental and numerical studies of the processes responsible for fast gas heating in pure nitrogen and in nitrogen/oxygen mixtures in the afterglow of nanosecond capillary discharge are performed. The peculiarities of the fast gas heating at conditions of the nanosecond discharge at high specific deposited energy at high reduced electric field are discussed. The modification of the kinetic scheme currently in use is proposed
24
Martin, Christopher M. "Pressure dependence of the luminescence and Raman modes in polyfluorene." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/4425.
Full textAbstract:
Thesis (Ph.D.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (February 28, 2007) Vita. Includes bibliographical references.
25
Couëdel, Lénaïc Gaël Hervé Fabien. "Nanoparticle formation and dynamics in a complex (dusty) plasma : from the plasma ignition to the afterglow." Connect to full text, 2008. http://hdl.handle.net/2123/4121.
Full textAbstract:
Thesis (Ph. D.)--University of Sydney, 2009.Includes graphs and tables. Cotutelle thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Complex Plasma Laboratory, School of Physics, Faculty of Science, University of Sydney and the degree of Docteur de l'Université Orléans. Title from title screen (viewed May 5, 2009) Degree awarded 2009; thesis submitted 2008. Includes bibliographical references. Also available in print form.
26
Couedel, Lenaic Gael Herve Fabien. "Nanoparticle formation and dynamics in a complex (dusty) plasma: from the plasma ignition to the afterglow." Thesis, The University of Sydney, 2008. http://hdl.handle.net/2123/4121.
Full textAbstract:
Complex (dusty) plasmas are a subject of growing interest. They areionized gases containing charged dust particles. In capacitively-coupled RF discharges, dust growth can occur naturally and two methods can be used to grow dust particles: chemically active plasmas or sputtering. The growth of dust particles in argon discharges by RF sputtering and the effect of dust particles on theplasma have been investigated from the plasma ignition to the afterglow. It was shown that plasma and discharge parameters are greatly affected by the dust particles. Furthermore, plasma instabilities can be triggered by the presence of the dust particles. These instabilities can be due to dust particle growth or they can be instabilities of a well established dust cloud filling the interelectrode space. When the discharge is switched off, the dust particles act like a sink for the charge carrier and consequently affect the plasma losses. It was shown that the dust particles do keep residual chargeswhich values are greatly affected by the diffusion of the charge carriers and especially the transition from ambipolar to free diffusion.
27
Couedel, Lenaic Gael Herve Fabien. "Nanoparticle formation and dynamics in a complex (dusty) plasma: from the plasma ignition to the afterglow." University of Sydney, 2008. http://hdl.handle.net/2123/4121.
Full textAbstract:
Doctor of Philosophy(PhD)Complex (dusty) plasmas are a subject of growing interest. They areionized gases containing charged dust particles. In capacitively-coupled RF discharges, dust growth can occur naturally and two methods can be used to grow dust particles: chemically active plasmas or sputtering. The growth of dust particles in argon discharges by RF sputtering and the effect of dust particles on theplasma have been investigated from the plasma ignition to the afterglow. It was shown that plasma and discharge parameters are greatly affected by the dust particles. Furthermore, plasma instabilities can be triggered by the presence of the dust particles. These instabilities can be due to dust particle growth or they can be instabilities of a well established dust cloud filling the interelectrode space. When the discharge is switched off, the dust particles act like a sink for the charge carrier and consequently affect the plasma losses. It was shown that the dust particles do keep residual chargeswhich values are greatly affected by the diffusion of the charge carriers and especially the transition from ambipolar to free diffusion.
28
Žáková, Marie. "Optická emisní spektroskopie dohasínajícího plazmatu ve směsi dusík-argon." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2009. http://www.nusl.cz/ntk/nusl-216566.
Full textAbstract:
The study of plasmas generated in pure nitrogen and their afterglows are a subject of many hundreds works bringing a lot of information about the kinetic processes and energy transfer reactions. The effect of nitrogen pink afterglow has a specific position among the other kinds of discharges and post-discharges. The post-discharge, and especially the pink afterglow, is extremely sensitive to the presence of various impurities and experimental conditions (total gas pressure in a discharge tube, temperature, etc.) because of their significant influence on all kinetic processes. That is the reason, why it is so important to study this processes. The DC flowing afterglow (generated using the hollow molybdenum electrodes in the distance of 12 cm, power ± 290 W) was used for the experimental part of this work. The discharge was created in Pyrex discharge tube at different concentration ratio of nitrogen and argon. The total gas presure was in range from 500 Pa to 5000 Pa. The emission spectra of post-discharge were recorded by TRIAX 550 spectrometer with CCD detector in the range of 320-780 nm. The vibrational populations at individual vibrational levels were calculated using the emission bands of the first (N2 (B 3g) N2 (A 3u+)) and the second (N2 (C 3u) N2 (B 3g)) positive and the first negative (N2+ (B 2u+) N2+ (X 2g+) nitrogen spectral systems. The dependencies of intensity on decay time and relative vibrational populations on argon concentration and pressure were obtained. The pink afterglow was very sharp in pure nitrogen at low pressure. With the increasing total pressure it was shifted to the later decay times and it was visible for longer time, too. The same effect was observed with the increase of argon concentration in the gas mixture. At the highest argon concentrations, especially at lower pressure, the effect of pink afterglow dissapeared. The knowledge of these processes can give the solution of all kinetic reactions in plasma and this can be used in plasma chemistry and for development of new technologies. This will be a subject of further intensive studies.
29
CLAUSEN, LAURA. "cut.suction.remove.suction.sew." Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-20713.
Full textAbstract:
This project is dealing with the human body and surgical modifications. I am wondering how to achieve the aim of provoking compassion, rejection and attraction in one collection. I would like to deeply move the sensation of your own body by showing deformed and reconstructed bodies.Cut off body parts and re-sew them somewhere else…I want to show something that is considered to be disgusting in a context where you would not expect to meet it.Furthermore, I would like to show that anything that looks normal disgusts you in an abnormal size or position.I want people to discover such elements at a second glance and I chose this theme also in order to provoke myself. I was wondering how it would affect my work by chosing a topic that irritates myself.The background for this project is built on a two year research and I am going to highlight the decisions along the way.I do relate my work strongly to Matthew Barneys way of creating and I got influenced by his aesthetics. But also the methods I used were significant for my end result which I am showing in form of clinical reports in which each character and its personal story is described.This report ends with a discussion part where I evaluate the result and my competence.Program: Master Programme in Fashion Design
30
Milligan, Daniel Bennett. "Selected reactions of ions and molecules in a flowing afterglow-selected ion flow/drift tube (FA-SIFDT)." Thesis, University of Canterbury. Chemistry, 2000. http://hdl.handle.net/10092/5715.
Full textAbstract:
The work presented herein revolves around the design, installation, testing, and use of a new flowing afterglow-selected ion flow drift tube (FA-SIFDT) at the University of Canterbury. This is the latest in the series of FA and SIFT apparatus that have been installed at Canterbury.
The second chapter contains a detailed description of the new instrument. Also present is a description of the characterisation of the new FA-SIFT in particular a comparison of two different types of venturi inlet, viz. an annulus and a hole type injector. The performance of both of these types of venturi inlet with respect to pumping efficiency, signal transmission, dissociation of weakly bound cluster ions, and the isomerisation of ions during injection. Despite the greater mechanical complexity of the annulus injector it is concluded that the annulus injector is slightly superior to the hole type injector, predominantly when the injection of ions needs to be at low energy.
Next a new application of the SIFT, namely its use in the real time detection, identification and quantification of trace components in gas samples, is presented. This technique has only recently been developed by overseas researchers and its use at Canterbury has been facilitated by the new FA-SIFDT. The technique has been applied to several systems: the analysis of the changes in the largest trace components of human breath (ammonia, acetone, isoprene) during exercise; the monitoring of breath concentrations of organic solvents following exposure; and the headspace analysis of the gases emitted by soil following fertilisation with an artificial urine solution.
The reactions of H3+, N2H+, and H3O+ with thirteen different hydrocarbons have been investigated. The rate coefficients and product distributions of these reactions were investigated in order to obtain a better understanding of exothermic proton transfer reactions. The H3+ was generated in two different manners in an effort to get accurate data about the products of proton transfer from ground state H3 . As expected, in most cases where the proton transfer was exothermic a rate coefficient just less than the collision rate was observed. The reactions became more dissociative as more energy was placed into the collision complex with the channels that predominated usually being between 100 and 200 kJ mol-1 exothermic.
The proton affinity of cyanogen (C2N2) has been investigated using the FA-SIFDT. The new value has been determined using the equilibrium method with reference to the C2N2/C2H2 and CH3Cl/C2N2 cycles. The new value is 651±2 kJ mol-1 some 24 kJ mol-1 less than the previously tabulated value. The reactions of methylated cyanogen were also investigated with the intention of determining the methyl cation affinity of cyanogen. Instead it has been determined that the CH3+.C2N2 adduct is strongly bonded, a characteristic that has previously been observed for alkyl ion-cyanide functionality type adducts.
Two classes of reaction relevant to the lower cosmic ray-induced ionosphere of Saturn's largest moon Titan have been investigated. The first class is the bimolecular reactions of the N3+ and N4+ ion species with a range of hydrocarbons likely to be present in Titan's atmosphere. These ionic species will be formed deep into Titan's atmosphere by the termolecular association of N+ and N2+ (the primary ions formed in Titan's atmosphere) with nitrogen. The association reactions of some of the terminal ions in Titan's atmosphere, viz. H3O+, HCNH+ and c-C3H3+, with methane, ethylene and acetylene in the presence of both helium and nitrogen bath gases. The termolecular reaction rate coefficients are greatly enhanced in the presence of a nitrogen carrier gas. Preliminary results of an investigation into the structure of the HCNH+.C2H4 and HCNH+.C2H2 adducts is also presented.
The termolecular association of the CH2CHCN+ and CH2CHCNH+ ions derived from acrylonitrile with neutral acrylonitrile have been investigated over a wide range of pressure in both the SIFT and an ion cyclotron resonance (ICR) mass spectrometer. This has enabled the pressure dependence of these two reaction to be experimentally investigated and theoretically modelled. In the non-protonated case
(CH2CHCN+) there is a competition between termolecular association and bimolecular reaction to give CH2CHCNH+. The reaction is observed to pressure saturate without a complete conversion to termolecular kinetics, an assumption made by the commonly used single-well model for association. A different, double-well, association mechanism is proposed for this reaction and modelled theoretically giving an acceptable fit. The CH2CHCNH+/CH2CHCN system shows only termolecular kinetics and is well modelled by a single-well model.
Work begun by earlier researchers at Canterbury on the reactions of ionic species with neutral carbon atoms has been continued. However an effective method for forming neutral carbon atoms has still not been found. The ultraviolet photolysis of carbon suboxide (C3O2) was hoped to solve this problem, however the wavelength of photolysis used was too long to get any significant C atom production. A vacuum UV flash system may be required.
31
Levaton, Jacques. "Produção de espécies ativas de N2+ e CN numa pós-descarga de N2-CH4 em regime de pink afterglow :." Florianópolis, SC, 2000. http://repositorio.ufsc.br/xmlui/handle/123456789/79316.
Full textAbstract:
Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico.Made available in DSpace on 2012-10-18T02:02:35Z (GMT). No. of bitstreams: 0Bitstream added on 2014-09-25T19:13:39Z : No. of bitstreams: 1 161521.pdf: 48732743 bytes, checksum: 5ba6bc8e27f523d283b5c55a82efcce2 (MD5)
Neste trabalho foram determinadas as condições experimentais necessárias para a geração do regime de pós-descarga denominado de "pink afterglow" numa descarga D.C. de N2 em fluxo. Fortes emissões oriundas dos 1o sistema negativo e 1o e 2o sistemas positivos do nitrogênio foram detectadas na região de pós-descarga até distâncias superiores a 15 cm a partir do final da descarga. Um modelo cinético para a formação das espécies radiativas responsáveis pelas emissões foi proposto para o regime de "pink afterglow". Constatou-se que, fundamentalmente são os processos vibracionais os precursores da excitação dos estados eletrônicos (B3Pg, v), (C3Pu, v) e da ionização na "pink", a qual apresenta dois mecanismos de geração distintos pela temperatura vibracional e tempo de residência das espécies. No intuito se estudar a possibilidade da tratamentos de nitretação e carbonitretação de aço no regime de "pink afterglow", introduziu-se CH4 na região de pós-descarga. Constatou-se que traços deste gás são suficientes para inibir os principais mecanismos da "pink" destruindo sua emissão. Neste caso, evidencia-se uma significativa produção de radicais CN pela forte emissão do sistema violeta do CN. Resultados preliminares sobre tratamentos de nitretação e carbonitretação em pós-descargas de N2-CH4 em regime de "pink afterglow"são apresentados.
32
Teslíková, Ivana. "Studium dohasínajícího dusíkového plazmatu pomocí titrace rtuťových par." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2012. http://www.nusl.cz/ntk/nusl-216820.
Full textAbstract:
The aim of this master thesis is a study of nitrogen post-discharge by mercury vapours titration. The nitrogen post-discharge is investigated for many years theoretically as well as for a practical use. The object of this master thesis is a study of kinetic processes ongoing at titrations of mercury vapours during the nitrogen post-discharge at different pressures and applied powers. All experimental data were obtained from an optical emission spectroscopy of nitrogen post-discharge. DC discharge in flowing regime was chosen for measurements. The first part of experiments was carried out at the constant discharge current (100 mA), voltage (1300 V) and wall temperature (300 K). The total gas pressure was varied in range of 500-3000 Pa at nitrogen flow in range of 0.12-0.68 l/min. Nitrogen flow values were arranged to obtain constant nitrogen flow velocity for all gas pressures. The second set of experiments studied power dependencies. The current was varied in the range of 50-200 mA for constant voltage 1300 V. The total gas pressure in this case was 1000 Pa. Mercury vapours were introduced into the system by titration tube at different post-discharge time. The nitrogen pink afterglow effect was well visible at all experimental conditions. This effect corresponds to the maximum intensity of light emission, which expresses as considerable growth of characteristic pink radiation in the post-discharge time. Optical emission spectra of post-discharge were taken in the range of 320-780 nm. Besides three nitrogen spectral systems (first and second positive and first negative), the mercury line at 254 nm was recorded in the second order spectrum at 508 nm under these conditions if mercury was added. This spectral line is excited under post-discharge conditions by collisionally induced resonance energy transfer from nitrogen highly vibrationally excited ground state metastables and it opens an unique technique for their monitoring. The dependence of relative intensities on decay time for mercury spectral line and selected nitrogen spectral systems at different titration positions were measured. The relative intensities of nitrogen bands decrease with increasing of mercury line relative intensity for all total gas pressures. The pink afterglow phenomenon shifts to the later decay times with the increasing of total gas pressure. In the case of experiments at different power, it can be seen that with decreasing power mercury spectral line intensity decreases in post-discharge time. The first detailed tests of the unique detection for highly excited of nitrogen metastables were completed. However this master thesis is concentrated on the basic research which supports better indication of kinetic processes and reactions leading to transformation of excitation energy, this new knowledge should be applied in future also in technologies based on the long-lived metastable induced reactions.
33
MARONGIU, MARCO. "Broadband modelling of relativistic explosions." Doctoral thesis, Università degli studi di Ferrara, 2020. http://hdl.handle.net/11392/2488013.
Full textAbstract:
In the new transient sky era, the progenitors of relativistic explosions, such as gamma-ray bursts (GRBs) and relativistic supernovae (SNe), are the focus of forefront research.
Broadband observations of nearby short GRB170817A -whose gravitational waves were detected by LIGO/VIRGO- and the recent detection at TeV energies of two bright GRB afterglows (190114C and 180720B) with the MAGIC and HESS Cherenkov telescopes heralded the birth of so-called multi-messenger astronomy.
GRB afterglows, originating from the interaction between the ejecta and the circumburst medium, help constrain the radiation mechanism, the relativistic shock microphysics, the circumburst environment, the structure and geometry of the relativistic jet. Observations of radio afterglows are key to understand the reverse shock, which links directly to the nature of the outflow and, consequently, to the progenitor itself. On the other hand, they can hardly be observed with current radiotelescopes because of their faintness (mJy or sub-mJy). Recently, several radio followup campaigns improved the observational coverage of the lower part of the emission spectrum, but an exhaustive picture of GRB afterglows is still missing.
I developed an approach focused on broadband modelling (with particular attention to the radio frequencies) through the Python code called sAGa (Software for AfterGlow Analysis). After successfully testing it on various GRB afterglows (120521C, 090423, and 050904), I applied it to long GRB160131A, whose data show evidence for energy injection and jetted emission. Radio light curves are characterised by several peaks, that could be due to either interstellar scintillation (ISS) effects or multi-component structure. My results show that the data can hardly be explained self-consistently with the standard model of GRB afterglows.
To help collect more radio data on GRB afterglows, I coordinated radio campaigns with Sardinia Radio Telescope (SRT) to observe two GRB radio afterglows (181201A and 190114C).
Although they have come up with no detection, they fostered the definition and the comparative analysis of three detection methods for faint radio sources through single-dish imaging, in terms of sensitivity and robustness: quick-look (a smart but rough approach), source extraction (typical of high-energy astronomy), and fitting procedure with a 2-Dimensional Gaussian (a more sophisticated approach). The new methodology for the SRT data analysis (1) pushes down the sensitivity limits of this radiotelescope -with respect to more traditional techniques- at ~1.8 mJy, and (2) highlights the need for accurate knowledge of the background.
L-GRBs are associated with type Ic broad-line supernovae (Ic-BL SNe). This connection can be observed only at redshift z < 1 because of the intrinsic faintness of SNe. In this context, I analysed Ic-BL SN2014ad, detected only in optical. The proximity of the source (~26 Mpc) and the radio/X-ray observations turned into very deep constraints on (1) the progenitor mass-loss rate, (2) the total energy of the ejecta, and (3) the explosion geometry. I considered two synchrotron emission regimes (uncollimated non-relativistic ejecta, typical of ordinary SNe); off-axis relativistic jet, such as those seen in GRBs), showing that off-axis low-energy jets expanding in a low-density medium cannot be ruled out even in the most nearby BL-Ic SNe.Nella nuova era dell'esplorazione del cielo transiente, i progenitori di esplosioni relativistiche -come i lampi gamma (GRB) e le supernovae relativistiche (SN)- sono tra i protagonisti più importanti della ricerca. Le osservazioni multi-frequenza del vicino GRB170817A -le cui onde gravitazionali sono state rilevate dagli interferometri LIGO/VIRGO- e la recente scoperta alle altissime energie degli afterglow associati a due GRB brillanti (190114C e 180720B) con i telescopi Cherenkov MAGIC e HESS hanno suggellato la nascita dell'astronomia multi-messaggera. Lo studio dell'afterglow dei GRB, originato dall'interazione tra la materia espulsa e il mezzo circostante, è fondamentale per comprendere i meccanismi di emissione, la microfisica dello shock relativistico, le proprietà del mezzo circostante e del getto. Gli afterglow radio dei GRB -per quanto difficili da osservare per la loro intrinseca debolezza (dell'ordine del sub-mJy)- sono cruciali per comprendere appieno questi aspetti, e in particolare lo shock inverso, che a sua volta dipende dalle proprietà della materia espulsa e quindi dal progenitore stesso del GRB. Anche se diverse campagne osservative hanno migliorato la copertura della parte radio dello spettro di emissione, ad oggi manca un quadro esaustivo degli afterglow. In questo contesto mi sono occupato di modellizzare l'emissione multi-frequenza degli afterglow, con particolare attenzione al radio, con la realizzazione del codice Python sAGa (Software for AfterGlow Analysis). Dopo aver testato con successo {\sc sAGa} su vari afterglow di GRB (120521C, 090423 e 050904), l'ho utilizzato nel caso di GRB160131A, i cui dati suggeriscono l'iniezione di energia da parte del progenitore, e la presenza di un getto. Inoltre, l'insolita presenza di picchi nelle curve di luce radio potrebbe essere dovuta a effetti di scintillazione interstellare. I miei risultati mostrano che i dati multi-frequenza sono difficilmente spiegabili nell'ambito del modello standard degli afterglow. Al fine di incrementare i dati radio, ho coordinato una serie di campagne osservative con il Sardinia Radio Telescope (SRT) per gli afterglow di GRB181201A e GRB190114C. Nonostante queste non abbiano portato alla rivelazione degli stessi, mi hanno offerto la possibilità di confrontare tre metodi per rivelare sorgenti deboli: quick-look (il meno accurato), source extraction (tipico dell'analisi ad alte energie) e il fit con una Gaussiana bi-dimensionale. La messa a punto di una nuova metodologia per l'analisi dei dati di SRT (1) ottimizza la rivelazione di una sorgente debole ad un flusso minimo rivelabile di ~1.8 mJy, e (2) evidenzia l'importanza di un'accurata conoscenza del fondo. I GRB lunghi sono associati alle Ic broad-line (Ic-BL) SNe. Ad oggi il legame GRB/SN è testabile solo per i GRB a redshift z < 1 per la debolezza intrinseca delle SNe. In questo contesto ho analizzato Ic-BL SN2014ad, rivelata solo in ottico. La vicinanza di questa sorgente (~26 Mpc) e le osservazioni in radio e raggi-X hanno permesso di vincolare profondamente (1) il tasso di perdita di massa del progenitore, (2) l'energia totale della materia espulsa a grande velocità e (3) la geometria dell'esplosione. Ho considerato due regimi di emissione di sincrotrone (isotropa con espansione sub-relativistica, tipica delle normali SN; relativistica con getto osservato fuori asse, come nei GRB), dimostrando che i getti poco energetici osservati fuori asse in un mezzo a bassa densità non possono essere esclusi nemmeno per una BL-Ic SN così vicina.
34
Brüggemann, Martin [Verfasser]. "Development, characterization, and application of flowing atmospheric-pressure afterglow ionization for mass spectrometric analysis of ambient organic aerosols / Martin Brüggemann." Mainz : Universitätsbibliothek Mainz, 2015. http://d-nb.info/1079036709/34.
Full text
35
Wong, Yuen-lam. "Transient radiation emission from astrophysical jets." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B39378512.
Full text
36
Wong, Yuen-lam, and 黃菀林. "Transient radiation emission from astrophysical jets." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39378512.
Full text
37
Kuhlmann, Christopher [Verfasser], and Carsten [Gutachter] Engelhard. "Optimization and application of flowing atmospheric-pressure afterglow mass spectrometry for direct surface sampling and quantitative analysis / Christopher Kuhlmann ; Gutachter: Carsten Engelhard." Siegen : Universitätsbibliothek der Universität Siegen, 2019. http://d-nb.info/1206733969/34.
Full text
38
Suchomel, Filip. "Porovnání světelných parametrů různých světelných zdrojů předních světlometů vozidel." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-402104.
Full textAbstract:
This thesis is focused on comparison of parameters of light sources (halogen, xenon, LED) installed in Skoda Octavia 3rd generation. The opening part solves analysis of the current state of lighting technology and its impact on traffic safety. The next part is focused on general parameters of light, construction of light sources, optical systems and adaptation of the human eye to various light conditions, especially contrast. The practical part is focused on comparing the contrast values of individual light sources in relation to the dark and lightly dressed pedestrian in the area without artificial lighting.
39
Kabeláčová, Kateřina. "Diagnostika dohasínajícího dusíkového plazmatu metodou optické emisní spektroskopie." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2018. http://www.nusl.cz/ntk/nusl-316179.
Full textAbstract:
The aim of this thesis is diagnose post-discharge nitrogen plasma with optical emission spectroscopy. There is long interest of investigated of nitrogen post-discharge plasma and study how to use it in theory as well as in practice. All results were measured with method of optical emission spectroscopy of post-discharge plasma. Discharge was generated by direct-current voltage generator with flowing regime. In this thesis was used for different series of experiments. First experiment was performed with adding water vapour into argon plasma. Measuring was processed at constant current 140 mA, voltage 1.5 V and pressure 1 000 Pa. It was changed flow rate and for each individual flow rate was measured in range 1–25 cm from end of active discharge. Second experiment was with adding nitrogen into argon plasma. Measuring was processed at constant current 140 mA, voltage 1.5 V and pressure 1 000 Pa. We were changing flow rate of nitrogen (0,2 sccm, 0,4 sccm and 0,8 sccm). For each individual flow rate was same experiment with changing distance from active discharge. Third experiment was about adding mercury vapour into nitrogen post-discharge. Measuring was processed at constant current 120 mA, voltage 3.5 V and pressure 1 000 Pa. Measuring was performed with two configuration: with diaphragm and without it. Last experiment was about adding air into argon plasma. Measuring was processed at constant current 140 mA, voltage 1.0 V and pressure 1 000 Pa. Temperature of outer face of tube was measured by thermocouple and infrared thermometer, was measured for last two experiments (argon – air and nitrogen). During experiments with pure nitrogen was visible phenomenon called pink afterglow which is manifested by noticeable increase pink coloration. Optical emission spectrums post-discharge was take at various range of wavelength. At argon with water vapour was 280–600 nm and at adding nitrogen into argon was at range 320–500 nm. At added mercury vapour into nitrogen was 320–600 nm. For experiment argon – air was wavelength range 320–600 nm. From results of experiments were designed dependencies of calculated intensity from measured spectra on distance from active discharge. Also were constructed dependencies of measured temperature on distance from active discharge.
40
MacLean, Garett M. MacLean. "Detection of Metal and Metal-Ligand Ions from Solid and Liquid Samples with a Flowing Atmospheric-Pressure Afterglow (FAPA) Source Coupled with Mass Spectrometry." Kent State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=kent1501251568218144.
Full text
41
Turpin, Damien. "Etude des objets transitoires à haute énergie dans l'univers dans l'ère des observations multi-messager." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30371/document.
Full textAbstract:
L'Univers est continûement le théâtre d'événements explosifs capables de relâcher une énorme quantité d'énergie sur des courtes échelles de temps. Ces sources transitoires comme les sursauts gamma, les supernovae ou les noyaux actifs de galaxie sont souvent associées à des objets extrêmes comme des étoiles à neutrons ou des trous noirs. De manière générale, ces sources émettent des radiations électromagnétiques dans une large bande spectrale voire sur la totalité du spectre pour les cas les plus extrêmes. Dès lors, une analyse multi-longueur d'onde est vitale pour étudier et comprendre la physique complexe de ces objets. De plus, au voisinage de ces sources, des particules (rayons cosmiques, RC) pourraient être efficacement accélérées jusqu'à des énergies très elevées dans des processus de chocs violents. L'interaction de ces RCs avec l'environnement peut conduire à la production d'un nombre significatif de neutrinos de hautes énergies. Par conséquent, l'étude des objets transitoires par le biais de l'astronomie neutrino offre la possibilité d'identifier enfin la nature des puissants accélérateurs cosmiques.Cette thèse est dédiée à l'étude de deux sources transitoires parmi les plus extrêmes dans l'Univers : les sursauts gamma (en anglais, Gamma-Ray Bursts : GRBs) détectés il y a ~ 50 ans et les sursauts radio (en anglais, Fast Radio Bursts : FRBs) fraîchement découverts il y a ~ 15 ans. Ces sources sont caractérisées par l'émission "prompte" d'un flash gamma (keV-MeV) durant de quelques ms à plusieurs secondes dans le cadre des GRBs et d'un flash intense en radio (GHz) durant quelques ms pour les FRBs. Dans le cas des GRBs une émission rémanente dite "afterglow" est observée dans une large gamme spectrale (X, visible et radio) alors que jusqu'à présent aucune autre contrepartie électromagnétique provenant d'un FRB n'a été découverte. Ces dernières années des modèles d'émission multi-longueur d'onde et multi-messager ont été développés afin d'expliquer ces 2 phénomènes. L'objectif majeur de ce travail de thèse est de tester ces modèles d'émission afin de contraindre la physique et la nature de ces deux objets. Pour cela, une analyse détaillée des propriétés physiques de l'émission afterglow des GRBs a été menée grâce à un large échantillon de données collectées ces 20 dernières années par diverses télescopes. Cette étude a permis de mettre en évidence les lacunes et les réussites du modèle GRB dit "standard" mais aussi les liens physiques subtils existant entre l'émission prompte des GRBs et leurs rémanences. Une recherche de signal neutrino en coïncidence avec les GRBs/FRBs a aussi été réalisée avec le télescope à neutrinos ANTARES. Les résultats sont décrits dans cette thèse ainsi que les contraintes apportées sur les processus d'accélération des particules durant ces phénomènes transitoires. Enfin, ce manuscrit rend compte des différents programmes d'observations innovants qui ont été engagés sur les télescopes optiques TAROT et Zadko et le télescope à neutrinos ANTARES afin de contraindre la nature des progéniteurs des GRBs/FRBsThe Universe is continuously the scene of explosive events capable of releasing a tremendous amount of energy in short time scales. These transients like Gamma-Ray Bursts, Supernovae or Active Galactic Nuclei are often associated with extreme objects such as neutron stars or black holes. Generally, these sources emit light in a large spectral energy range and sometimes in the whole electromagnetic spectrum for the most extreme cases. Thus, a multi-wavelength analysis is crucial to study and understand the complex physical processes at work. Furthermore, in the vicinity of these sources, particles (cosmic-rays, CRs) could be efficiently accelerated up to very high energies by violent shock mecanisms. The interaction of these CRs with the surrounding environment may lead to a substantial production of high-energy neutrinos. Therefore, the study of the high-energy transient objects through neutrino astronomy offer the possibility to finally identify the nature of the powerful cosmic accelerators a hundred year after the discovery of the cosmic-rays.This thesis is dedicated to the study of two transient sources among the most extreme ones observed in the Universe: the Gamma-Ray Bursts (GRBs) detected ~ 50 years ago and the Fast Radio Bursts (FRBs) newly discovered ~ 15 years ago. These sources are characterised by the "prompt" emission of a gamma-ray flash (keV-MeV) lasting few ms up to few seconds for GRBs and an intense pulse of radio light (GHz) lasting few ms for FRBs. In the case of GRBs a late broadband afterglow emission is observed in X-rays/optical/radio domain while up to now no other electromagnetic counterpart has ever been detected in coincidence with any FRBs. These last years, many models predicting a multi-wavelength and a multi-messenger emission from these two phenomena have been developped. The main goal of this thesis work is to test these models in order to constrain the physics and the nature of the GRBs/FRBs. To do so, a detailed analysis on the physical properties of the GRB afterglow emission was made thanks to a large set of data collected these last 20 years by various facilities. The study reveals the major problems but also the successes encountered with the so-called "standard" GRB model. Subtle connections between the prompt and the afterglow emission are also discussed. In addition, a search for a neutrino signal from GRBs/FRBs was realised with the ANTARES neutrino telescope. The results are described in this thesis as well as the constraints on the particle acceleration mecanisms occuring during these transient phenomena.At last, this manuscript presents the different innovative observational programs realised in the optical domain with the TAROT and Zadko telescopes and in the astroparticle side with the ANTARES neutrino telescope in order to probe the nature of the GRBs/FRBs progenitors
42
Martínek, Michal. "Osvětlovací technika moderních vozidel a měření dohlednosti na dosvit hlavních světlometů." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-232559.
Full textAbstract:
This magister’s thesis is about modern lighting of vehicles, the visual range and afterglow in poor visibility. The first part of the thesis provides a detailed analysis of the current situation and problems, including a comprehensive description of the sources of light radiation, lamps, structures, and describe the systems used in modern lighting technology of vehicles. In the second part of the thesis there are the scientific methods to determine the issue of visual range and afterglow of the headlights. The second part is about the application of acquired techniques to detect an afterglow and the visual range of vehicles with modern headlights with a light source with xenon lamp, compared with a vehicle with a halogen lamp and a vehicle with an older halogen headlight.
43
Barckholtz, Cynthia. "A prelude to chemical kinetics : computational study of the elementary paths for the oxidation of aromatic hydrocarbons and experimental design of a flowing afterglow-selected ion flow tube /." The Ohio State University, 1998. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487952208108753.
Full text
44
Altaweel, Ayman. "Synthèse de nanostructures d'oxyde de cuivre par micro-post-décharge micro-ondes à pression atmospherique." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0059/document.
Full textAbstract:
L’étude de l’oxydation de films minces de cuivre déposés par pulvérisation magnétron sur des substrats de silicium et de verre a été menée au moyen d’une micro-post-décharge micro-ondes dans l’objectif de faire croître de manière localisée des nanostructures contrôlées d’oxyde. L’utilisation de plasma permet d’utiliser des atomes d’oxygène plutôt que de molécules d’oxygène et de pouvoir diminuer les températures de synthèse d’environ 100° typiquement. Il a ainsi été possible de faire croître des nanostructures hiérarchiques formées de nanoparois en boule, des nanoparois d’épaisseurs variables, des nanofils et des nanoplots de CuO. Ces différentes nanostructures se forment à des instants successifs et se répartissent radialement par rapport au centre de l’impact de la post-décharge. Elles croissent en suivant des cinétiques paraboliques qui traduisent une limitation par un transport diffusionnel. La diffusion est externe et conduit la formation de porosités Kirkendall à l’interface substrat-cuivre. Les analyses TEM ne montrent pas d’orientation privilégiée. Les nanofils sont soit mono- soit bi-cristallins. Des contraintes de compression (respectivement de tension) ont été mesurées dans Cu2O (respectivement dans CuO). La taille de grain est plus élevée au centre que sur les bords du traitement. Cela permet la croissance de nanoparois et de nanofils de diamètres relativement importants près du centre alors qu’une taille de grains plus petites sur les extérieurs entraîne la formation de nanofils plus fins mais avec une densité surfacique supérieure. Les différents modèles de croissance existant ont été repris pour interpréter ces nouveaux résultatsOxidation of copper thin films deposited by magnetron sputtering on silicon and soda-lime glass substrates was performed by means of a microwave micro-afterglow to grow locally controlled nanostructures of copper oxide. The use of plasma discharges offers the possibility to handle oxygen atoms instead of oxygen molecules, which enable a substantial decrease in the synthesis temperature of about 100° typically. It was thus possible to grow hierarchical nanostructures made of nanowalls shaped in balls, nanowall with variable thicknesses, nanowires and nanodots of CuO. These different nanostructures forms successively and are distributed radially from the impact center of the post-discharge outwards. They grow by following parabolic growth rates that are due to a diffusion transport limitation. Outward diffusion occurs and creates a Kirkendall porosity at the substrate-copper interface. TEM analyses do not show any preferential orientation. Nanowires are either mono- or bi-cristals. Compressive (respectively tensile) stress was measured in Cu2O (respectively CuO). The grain size is larger in the center than on the edges of the treatment area. This enables the growth of nanowalls and nanowires with diameters pretty large close to the center whereas a smaller grain size on the edges leads to the formation of thinner nanowires but with higher surface density. The different existing growth models were considered to interpret these new results
45
Kuete, Saa Duclair. "Synthèse de nanostructures d’oxyde de ruthénium par plasma micro-ondes en post-décharge à la pression atmosphérique." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0057/document.
Full textAbstract:
Diverses nanostructures de dioxyde de ruthénium ont été synthétisées par oxydation locale du ruthénium massif et de films minces de ruthénium au moyen de plasmas micro-ondes Ar-O2 en post-décharge à la pression atmosphérique. Ces revêtements ont été déposés préalablement par pulvérisation magnétron. Une étude approfondie a été réalisée pour déterminer l’évolution radiale de la température de surface qui évolue typiquement entre 530 K et 900 K. L’utilisation d’un plasma permet un abaissement de la température d’oxydation par rapport à des conditions thermiques dans la mesure où l’oxygène moléculaire est excité ou dissocié, ce qui fournit des espèces plus réactives comme l’oxygène singulet ou l’oxygène atomique. Suivant le substrat utilisé et les conditions opératoires, des structures en lamelles distantes de 20-50 nm, des micro-oursins localisés, des nanofils longs et denses et des microcristaux peuvent être formés. Les nanostructures obtenues ont été caractérisées par différentes techniques (microscopies électroniques, diffraction des rayons X ou spectrométrie de masse des ions secondaires). Les analyses MET ne révèlent pas d’orientation privilégiée des nanofils qui sont généralement monocristallins. Des mécanismes de croissance des nanostructures très différents ont été observés et identifiés. S’il apparaît qu’il est impossible sur substrat massif de ruthénium d’obtenir des nanostructures uniformément réparties, il en va autrement avec des substrats recouverts d’une couche mince de ruthénium qui permettent de former de véritables tapis de nanofils. La possibilité de localiser la croissance des nanofils par ajout de sels alcalins a été étudiéeVarious ruthenium dioxide nanostructures were locally grown by the oxidation with an atmospheric pressure Ar-O2 microwave micro-afterglow of bulk ruthenium samples or thin films previously deposited by magnetron sputtering on silicon and silica. A special attention was paid to the distribution of the surface temperature of the sample which evolves typically between 530 K and 900 K. The use of plasma discharges allows a lowering of the temperature compared with the thermal oxidation conditions, given that molecular oxygen is excited or dissociated, which provides more reactive species such as singlet oxygen or atomic oxygen. According to the substrate used and the operating conditions, different nanostructures can be formed: lamellae separated by 20–50 nm, localized nano-sea urchins, high density of long nanowires and microcrystals. Nanostructures obtained were characterized by various techniques (electron microscopy, X-ray diffraction or secondary ion mass spectrometry). The grown RuO2 nanowires were determined to be generally single-crystalline with random crystallographic orientations. Very different growth mechanisms were observed and identified. Although it seems impossible to obtain uniformly distributed nanostructures on bulk ruthenium substrates, it is possible from substrates coated by a thin layer of ruthenium, which allows the formation of nanowire carpet. The possibility to localize the growth of nanowires by adding alkali salts has been studied. However, if the use of NaCl or KCl crystals locally enhances the nanowire density, they do not ensure systematically the growth of nanowires
46
Varela, Cardozo Karla Patricia Verfasser], Jochen [Akademischer Betreuer] [Gutachter] [Greiner, and Lothar [Gutachter] Oberauer. "Testing the standard GRB afterglow model with the snapshot method using multi-epoch multi-wavelength data / Karla Patricia Varela Cardozo ; Gutachter: Jochen Greiner, Lothar Oberauer ; Betreuer: Jochen Greiner." München : Universitätsbibliothek der TU München, 2017. http://d-nb.info/1135724938/34.
Full text
47
Galama, Titus Johannes. "Gamma-ray burst afterglows." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 1999. http://dare.uva.nl/document/91670.
Full text
48
Balharová, Gabriela. "Možnosti osvětlení vozidel pro zvýšení bezpečnosti silničního provozu." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-232650.
Full textAbstract:
This master’s thesis deals with the possibilities of illumination of motor vehicles. Thesis is divided into two sections, from which the first discusses precisely the possibilities of lighting of motor vehicles at the present time. What are the modern lighting techniques, that can be found on the market and what is their impact on safety enhancement in road traffic. Second section is about the practical measurement of low and high beam afterglow. This measurement is being compared between two types of headlamps, namely halogen headlights and xenon headlights. Part of the measurement is as well measurement of illumination intensity precisely for these headlights. The output of measurement is the creation of own illumination intensity diagrams and afterglow diagrams of particular headlights, in comparison to isolux diagrams provided by the headlights manufacturer. Consequently are solved the issues about utilization of the isolux diagrams in expert praxis.
49
Soural, Ivo. "Studium procesů v dohasínajícím plazmatu." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2011. http://www.nusl.cz/ntk/nusl-233321.
Full textAbstract:
The decaying plasma was studied by the optical emission spectroscopy. DC discharge created at 45 – 200 mA in Pyrex and Quartz tubes in flowing regime was used. The emission of three nitrogen spectral systems (1st and 2nd positive and 1st negative) were studied in time evolution for pressures of 500 – 5 000 Pa at two wall temperatures – ambient and liquid nitrogen (150 K inside the decaying plasma). Results showed that all three nitrogen systems (respectively N2(B, v), N2(C, v) and N2+(B, v) states as their origins) had their population maxima called pink-afterglow in the afterglow part. These maxima decreased with the increase of pressure for all systems, and moved to the later decay time. Maxima increased with discharge current (respectively power) and moved to shorter time. Populations at temperature of 150 K were measured due to the experimental arrangement from 17 ms, only, and thus pink aftergow maximum wasn’t observed (only at 5 000 Pa some maximum was recognized). Populations were smaller at 150 K that populations measured at laboratory temperature at the middle decay time (50-100 ms). At the late time, the populations were higher at lower temperature at lower pressure. Higher shifts (in intensity and decaytime) of pink afterglow maxima were observed in Quartz tube in comparison with their values in Pyrex tube. Besides the populations, rotational temperatures of selected bands of three observed spetral systems (for 1st negative 0-0 band, 1st positive 2-0 band and for 2nd positive 0-2 band) were measured. Rotational temperatures were monitored from presumption that this kind of temperature is equal to temperature of neutral gas (at local thermodynamic equilibrium). Results from 1st negative and 1st positive system showed strong decreasing of rotational temperatures up to about 10 ms at post-discharge begin, then temperatures were constant up to 20 ms of decay time and after that they grew up. Temperatures increased with the increase of current. The part with decreased temperature correlated with pink-afterglow part of post-discharge. Unfortunately, rotational temperatures of 2nd positive system had bad reproducibility and the time profile shape was opposite. Experimental results were compared with numerical kinetic model created by group of prof. Vasco Guerra at Instituto Supetior Técnico in Portugal. Several sets of conditions for simulation at 500 and 1 000 K in active discharge were applicable for the calculation corresponding to the experiment. Comparison of numerical simulation and experimental data done for N2(B) state demonstrated that maxima populations in pink afterglow are depended on the temperature difference between active discharge and post discharge. Maxima populations were supposed in pink afterglow disappeared if the same temperatures in active and post discharges were supposed. Temperature in active discharge is higher at higher apllied power, as it was showed from rotational temperatures observation. The results clearly showed that real temperature profile must be included into the kinetic model.
50
Perret, Hubert. "Radio "Afterglows" in Grossen Solaren Flares." [Zürich] : [ETH, Eidgenössische Technische Hochschule Zürich, Institut für Astronomie], 2003. http://e-collection.ethbib.ethz.ch/show?type=dipl&nr=140.
Full text