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KHOLIA, AKSHAT. « Thermal Hydraulic numerical analysis of Fusion superconducting magnet systems ». Doctoral thesis, Politecnico di Torino, 2013. http://hdl.handle.net/11583/2507886.
Texte intégralCoatanea-gouachet, Marc. « Quench detection and behaviour in case of quench in the ITER magnet systems ». Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4739/document.
Texte intégralThe quench of one of the ITER magnet system is an irreversible transition from superconducting to normal resistive state, of a conductor. This normal zone propagates along the cable in conduit conductor dissipating a large power. The detection has to be fast enough to dump out the magnetic energy and avoid irreversible damage of the systems. The primary quench detection in ITER is based on voltage detection which is the most rapid detection. The very magnetically disturbed environment during the plasma scenario, makes the voltage detection particularly difficult, inducing large inductive components in the coils and voltage compensations have to be designed to discriminate the resistive voltage associated with the quench. A conceptual design of the quench detection based on voltage measurements is proposed for the three majors magnet systems of ITER. For this, a clear methodology was developed. It includes the classical hot spot criterion, the quench propagation study using the commercial code Gandalf and the careful estimation of the inductive disturbances by developing the TrapsAV code.Specific solutions have been proposed for the compensation in the three ITER magnet systems and for the quench detection parameters which are the voltage threshold (in the range of 0.1 V- 0.55 V) and the holding time (in the range of 1 -1.4 s). The selected values, in particular the holding time, are sufficiently high to ensure the reliability of the system and avoid fast safety discharges not induced by a quench which is a classical problem
ZAPPATORE, ANDREA. « Modelling Innovative High Temperature Superconductors for Fusion Applications ». Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2935600.
Texte intégralBarber, Julien (Julien Victor). « Investigation of cryogenic cooling for a high-field toroidal field magnet used in the SPARC fusion reactor design ». Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/118738.
Texte intégralCataloged from PDF version of thesis.
Includes bibliographical references (pages 111-114).
Rare Earth Barium Copper Oxide (REBCO) High Temperature Superconducting (HTS) tapes are being considered for the Toroidal Field (TF) magnets of the highly compact, high-field SPARC Version 0 (V0) reactor design. The V0 design is set to operate at magnetic fields as high as 20 T, and operating temperatures ranging from 10-30 K. Due to the increase in range of operating conditions made available through the HTS-based magnets, a new set of cryogenic fluids are being considered for forced flow cooling. This thesis analyzes the thermophysical properties of helium, hydrogen, and neon, and constructs a numerical model to investigate the forced flow cooling for REBCO HTS tapes under the extreme heating conditions present in the SPARC V0 design. Four design criteria are used to assess each cryogen, including the current sharing temperature, fluid inlet temperature, cable pressure drop ([delta]P), and operating pressure. From the results of the model, neon is removed from consideration due to its high required pressure drop and low temperature margins imposed by the superconductor current sharing limit. Hydrogen provides the highest effective heat transfer rate operating at inlet conditions of 1.5 MPa and 15 K, but is constrained by safety considerations. Helium is also able to meet the current sharing condition, but with higher initial pressure and lower initial temperature. Using the numerical model, an analysis using the four design criteria finds an optimal operating condition for helium of 2.5 MPa and 10 K based on minimizing cable pressure drop ([delta]P) and inlet pressure, while maximizing the fluid's inlet temperature. With a target operating point defined, an experimental cryogenic flow loop is designed with the purpose of verifying the high heat transfer rates required for the high-pressure, supercritical helium flow in the SPARC reactor. The flow loop uses a pressure differential to drive flow at a target mass flow rate of 46 g/s. To simulate a plasma pulse, the fluid flow is subject to heat fluxes up to 45 kW/m² for a minimum duration of ten seconds.
Supported by the U.S. Department of Energy, Office of Fusion Energy Science Grant: DE-FC02-93ER54186
by Julien Barber.
S.M.
Dehnen, Matthias [Verfasser]. « Degenerative Veränderungen des angrenzenden Segments nach anteriorer zervikaler Diskektomie und Fusion : eine Magnet Resonanz Untersuchung im Langzeitverlauf / Matthias Dehnen ». Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2020. http://d-nb.info/1214240763/34.
Texte intégralBayer, Christoph M. [Verfasser]. « Characterization of High Temperature Superconductor Cables for Magnet Toroidal Field Coils of the DEMO Fusion Power Plant / Christoph M. Bayer ». Karlsruhe : KIT Scientific Publishing, 2017. http://www.ksp.kit.edu.
Texte intégralTalami, Matteo. « Modeling of the Toroidal Field Insert coil for the ITER Project ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/12916/.
Texte intégralLopes, Carmelo Riccardo. « Design and Simulation of Fast Discharge Units (FDUs) for Toroidal Field Coils of Divertor Tokamak Test (DTT) ». Doctoral thesis, Università degli Studi di Palermo, 2023. https://hdl.handle.net/10447/580087.
Texte intégralThis thesis summarizes the work carried out during the 3-year PhD course in the period between 2019 and 2022. As is well known in the scientific community, the very ambitious nuclear fusion project has required and still requires considerable resources and investments; The roadmap for large-scale nuclear fusion power generation is comprised of challenging missions. The ITER and DEMO projects, being international projects, require the collaboration (both from an economic and technical point of view) of different countries at European and non-European level; for this reason, the various technological aspects, which will then be implemented and applied in the final fusion reactors, are first analyzed, simulated, and managed by various bodies of the project member states (including Italy). One of the most important research facilities for these projects is located at the ENEA headquarters in Frascati (RM) and is called DTT (divertor tokamak test facility). The DTT structure is designed to explore all lines of plasma operating regimes relevant to ITER and DEMO; In particular, it will be possible to demonstrate the physical and technological feasibility of various divertor configurations. In this way it will be possible to integrate knowledge on alternative divertor concepts already tested on existing machines. Since the magnetic energy stored in superconducting magnets is of the order of 2GJ-4GJ (for DTT), in the event of a failure or quench there must be the possibility to extract it very quickly to safeguard the integrity of the Tokamak and superconductors. In this case, the so-called FDU systems (fast discharge unit) intervene, which basically consist of resistors to allow discharge and fast dissipation of energy. Protection is carried out by connecting a discharge resistor in series to each block of magnets divided into various groups depending on their electrical configuration. The main objective of this thesis so is to report all the models, simulations and results processed for the entire duration of the course of study as part of the development of Fast Discharge Units (FDU).
Hasnain, Bakhtiyar Asef, et Ademir Hodzic. « Design and Simulation of a Slotless Aircored PM Synchronous Generator ». Thesis, Uppsala universitet, Institutionen för elektroteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-425268.
Texte intégralBruzzone, Pierluigi. « AC losses in high current superconductors for nuclear fusion magnets / ». [S.l.] : [s.n.], 1987. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=8224.
Texte intégralBarth, Christian [Verfasser]. « High Temperature Superconductor Cable Concepts for Fusion Magnets / Christian Barth ». Karlsruhe : KIT Scientific Publishing, 2013. http://www.ksp.kit.edu.
Texte intégralLouzguiti, Alexandre. « Magnetic screening currents and coupling losses induced in superconducting magnets for thermonuclear fusion ». Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0574.
Texte intégralTokamaks aim at producing energy by thermonuclear fusion heating a hydrogen plasma up to 150 million K and confining it with an intense magnetic field created by magnets carrying important currents. Superconductivity is a very valuable asset in this field since it allows to reduce the size of the magnets and their energy consumption in exchange for cooling them down to cryogenic temperatures. However, in tokamaks, magnetic field variations occur (e.g. due to the central solenoid discharge) and generate induction losses in the magnets. If their temperature increases too much, they lose their superconducting properties in a brutal transition called "quench": to protect their integrity, they are then discharged and the magnetic confinement of the plasma is lost. We have therefore focused on the modeling of these losses - more precisely on the “coupling losses” - since their knowledge is crucial to safely adapt the cryogenic cooling of the magnets and predict the operating limits of the tokamak. In order to both enhance the physical understanding of this complex phenomenon and provide simple but realistic solutions that can easily be integrated in multiphysics platforms already heavily solicited by the modeling of other effects, we have chosen to adopt an analytical approach on this problem. The cables commonly considered for tokamaks presenting a rather complex architecture (several hundreds of strands twisted together in specific patterns), we have carried out analytical and experimental studies at the different scales of the cable; we then compare the results of our approach to other existing ones (e.g. numerical models) and, when possible, to the experiment
Nguyen, Christine. « Magneto-Hydrodynamic Activity and Energetic Particles - Application to Beta Alfvén Eigenmodes ». Phd thesis, Ecole Polytechnique X, 2009. http://pastel.archives-ouvertes.fr/pastel-00005642.
Texte intégralSorbom, Brandon Nils. « The effect of irradiation temperature on REBCO Jc degradation and implications for fusion magnets ». Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/120392.
Texte intégralCataloged from PDF version of thesis.
Includes bibliographical references (pages 143-154).
Recent advances in high temperature superconductors (HTS) have opened up a new parameter space for the design of tokamak fusion pilot plants. While previously the maximum on-axis field in a superconducting tokamak was limited to ~6 T, HTS allows tokamaks to be designed with much higher on-axis fields, leading to smaller reactor designs. For these designs, it is critical to determine the lifetime of modern HTS technology in an environment relevant to compact, high-field fusion reactors as well as develop strategies to mitigate this damage. While some studies have been undertaken to assess the lifetime of coated conductors in a fast neutron environment, facilities do not exist to perform cryogenic neutron irradiations at the present. In addition, reactor studies are costly and activate the samples, requiring long cooldown times and specialized analysis facilities to handle radioactive material. In order to complement reactor irradiation studies of HTS and determine whether elevated temperature irradiation has an effect on Jc degradation, REBCO coated conductors were irradiated with a 1.2 MeV proton beam at 80 K, 323 K, and 423 K. Proton irradiation at cryogenic temperatures was found to substantially reduce the amount of Jc degradation in the REBCO samples irradiated to high fluences, a result of great importance to superconducting REBCO magnets in fusion applications where the radiation will occur at T < 80 K. An analysis of temperature, field, and angle dependencies of Jc was performed to investigate the microstructural mechanisms behind the Jc degradation at different temperatures. The key mechanism driving the differences in Jc degradation was found to be radiation-enhanced diffusion at higher temperatures, leading to grain boundary widening between superconducting crystals which in turn blocked supercurrent transport through the conductor. Molecular dynamics simulations suggest that the same mechanism (enhanced diffusion to grain boundaries) also applies to neutron irradiations. This motivates a re-evaluation of previous REBCO neutron irradiation studies at temperatures between 323 K and 383 K, specifically with regards to predictions about REBCO lifetimes in a fusion environment. The work in this thesis suggests that at cryogenic temperatures, the Jc degradation observed in these studies could be substantially less than previously reported.
by Brandon Nils Sorbom
Ph. D.
Cordaro, Luigi. « Magnetic reconnection in fusion plasmas ». Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3422201.
Texte intégralQuesta tesi è dedicata allo studio sperimentale della riconnessione magnetica e ai fenomeni correlati che si verificano nei plasmi generati da RFX-mod, una macchina sperimentale molto flessibile per lo studio del confinamento magnetico dei plasmi per la fusione termonucleare. La riconnessione magnetica consiste in un riarrangiamento della topologia del campo magnetico, che determina una conversione di energia magnetica in calore e energia cinetica di particelle cariche. Essa si verifica ovunque nell’universo, essendo osservata nell’evoluzione dei brillamenti solari, nella interazione del vento solare con la magnetosfera della Terra e nei dischi di accrescimento delle stelle. La riconnessione magnetica avviene anche nei plasmi di laboratorio, specialmente nei processi di auto-organizzazione che si verificano nei plasma da fusione. In quest’ultimi, gli eventi di riconnessione magnetica sono particolarmente evidenti durante le attività sawtooth dei tokamak e negli eventi di rilassamento discreti (DRE) nei reversed field pinch (RFP) e sono coinvolti nella formazione di isole magnetiche associate alle instabilità ‘tearing’. Durante questi processi si verifica un cambiamento topologico delle linee del campo magnetico, che porta a nuove configurazioni di equilibrio di energia magnetica inferiore. Una comprensione completa e dettagliata della riconnessione magnetica è ancora mancante. Tale fenomeno rappresenta un importante argomento da studiare per una migliore comprensione di una grande varietà di fenomeni astrofisici e di laboratorio. Il lavoro di analisi presentato in questa tesi è principalmente basato sull’analisi dei dati sperimentali di RFX-mod, provenienti da sistemi di sonde elettrostatiche e magnetiche, posizionate all’interno della camera da vuoto. Le analisi sperimentali sono state affiancate anche da attività di modellizazione teorica. L’attività complessiva può essere divisa in due parti principali: nella prima è stata svolta una caratterizzazione dei fenomeni di riconnessione nei plasmi in configurazione RFP; la seconda è dedicata allo studio della rotazione delle isole magnetiche in scariche tokamak circolari. La caratterizzazione della riconnessione magnetica è stata effettuata analizzando i DRE in scariche RFP. Durante questi fenomeni, la perturbazione magnetica determina la formazione di modi toroidalmente localizzati m = 0, associati alla formazione di strutture di corrente poloidale. L’analisi ha dimostrato che queste strutture sono naturalmente soggette a frammentazione, la quale determina a sua volta una struttura di campo elettrico multi-scala che, come mostrato in letteratura, è in grado di accelerare efficacemente le particelle cariche. In effetti, è stata osservata l’accelerazione di ioni sovratermici, particolarmente evidenti nelle posizioni in cui si verifica la riconnessione magnetica, durante gli eventi discreti di rilassamento. Tali particelle hanno energia abbastanza alta da indurre una reattività da fusione, come dimostrano gli andamenti temporali dei flussi neutronici. Queste evidenze sperimentali dimostrano che la riconnessione magnetica può contribuire in modo efficace al riscaldamento del plasma nei dispositivi RFP. La seconda attività di ricerca principale è stata dedicata all’analisi della dinamica dei modi tearing nei plasmi di RFX-mod in configurazione tokamak. Tali modi tearing sono instabilità resistive, che si sviluppano sia nei plasmi tokamak che in quelli RFP. In presenza di resistività, le linee di campo possono rompersi e riconnettere, determinando un cambiamento nella topologia magnetica. La configurazione magnetica risultante è caratterizzata dalla presenza di isole magnetiche che, a loro volta, favoriscono il trasporto radiale di particelle e la riduzione del confinamento magnetico. I modi tearing costituiscono quindi un problema per il confinamento magnetico e la loro caratterizzazione è importante per poter proporre metodi di controllo al fine di migliorare le prestazioni del confinamento. Lo studio delle scariche tokamak ha incluso sia l’analisi dei dati sperimentali che una modellazione teorica della rotazione dei modi tearing basata sulle equazioni MHD a due fluidi. Il confronto dei risultati sperimentali con le previsioni del modello teorico ha mostrato che la rotazione delle isole magnetiche nei plasmi tokamak di RFX-mod è guidata principalmente dalla deriva diamagnetica. La variazione di quest’ultima può determinare, associate ad una modifica dei profili di pressione, al rallentamento della rotazione di tali modi, un fenomeno talvolta associato alla crescita delle instabilità e che può portare alla disruzione. Infine, è stata osservata una caratteristica oscillazione quasi-ciclica di ampiezza e frequenza dei modi tearing, chiamata ‘ciclo limite’. Questo comportamento è dimostrato essere accoppiato alla cosiddetta attività ‘sawtooth’ che si verifica nella regione centrale del plasma.
Michael, Andrew M. « Imaging schizophrenia : data fusion approaches to characterize and classify / ». Online version of thesis, 2009. http://hdl.handle.net/1850/9673.
Texte intégralAndersson, Sundén Erik. « Neutron Spectrometry Techniques for Fusion Plasmas : Instrumentation and Performance ». Doctoral thesis, Uppsala universitet, Tillämpad kärnfysik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-121615.
Texte intégralRenzetti, Reny Angela. « Estudo comparativo da recristalização de dois aços de atividade reduzida endurecidos por dispersão de óxidos (9%Cr e 13%Cr) ». Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/97/97134/tde-27082013-094247/.
Texte intégralThere is an increasing interest in the development of new, sustainable, clean and safe sources of energy. In view of these requirements, the development of advanced materials for future nuclear fusion reactors becomes essential. This work investigates the annealing behavior and the microstructural stability of two oxide dispersion strengthened steels with 9%Cr and 13%Cr ODS steels. These materials are potential candidates for structural applications in future fusion reactors. The two ODS steels were cold rolled to 80% thickness reduction. Samples were annealed in vacuum at temperatures of about 0.9 Tm, where Tm is the melting point. The microstructural characterization was performed by Vickers hardness testing, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) performed by a highresolution SEM. Important temperatures related to the phase transformations were determined with aid of dilatometry and differential thermal analysis (DTA). Magnetization curves as a function of applied magnetic fields up to 15 kOe were obtained for 9%Cr ODSEurofer. X-ray diffraction experiments were also performed on 9%Cr steel to evaluate the dislocation density in several metallurgical conditions. Results show that microstructural coarsening becomes significant when annealing is performed above 0.8 Tm. Below 800°C, static recovery is the main softening mechanism of these steels and the volume fraction of recrystallized grains is quite low. The resistance of these steels to recrystallization can be explained by the strong interaction between boundaries and mobile dislocations with fine particles of Y-based oxides. Contrastingly, coarse M23C6 particles act as preferential nucleation sites through the well-known particle stimulated nucleation (PSN) mechanism. Samples annealed above 800oC (austenitic phase field) display larger dislocation densities in the 9%Cr ODS steel. Results concerning to 13%Cr steel suggest the occurrence of martensitic transformation.
Samulski, Camille Clement. « Deceleration Stage Rayleigh-Taylor Instability Growth in Inertial Confinement Fusion Relevant Configurations ». Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/103703.
Texte intégralMaster of Science
The direction for the future of renewable energy is uncertain at this time; however, it is known that the future of human energy consumption must be green in order to be sustainable. Fusion energy presents an opportunity for an unlimited clean renewable energy source that has yet to be realized. Fusion is achieved only by overcoming the earthly limitations presented by trying to replicate conditions at the interior of stellar structures. The pressures, temperature, and densities seen in the interior of stars are not easily reproduced, and thus human technology must be developed to reach these difficult stellar conditions in order to harvest fusion energy. There are two main branches of developmental technology geared towards achieving the difficult conditions controlled nuclear fusion presents, magnetic confinement fusion (MCF) and inertial confinement fusion (ICF)[17]. Yet in both approaches barriers exist which have thwarted the efforts toward reaching fusion ignition which must be addressed through scientific discovery. Successfully reaching ignition is only the first step in the ultimate pursuit of a self sustaining fusion reactor. This work will focus on the experimental ICF configuration, and on one such inhibitor toward achieving ignition, the Rayleigh-Taylor (RT) instability. The RT instability develops on the surfaces of the fusion fuel capsules, targets, and causes nonuniform compression of the target. This nonuniform compression of the target leads to lower pressures and densities through the material mixing of fusion fuel and the capsule shell, which ultimately leads to challenges with reaching fusion ignition. The work presented here was performed utilizing the University of Chicago's FLASH code, which is a state-of-the-art open source radiation magneto-hydrodynamic (MHD) code used for plasma and astrophysics computational modeling [11]. Simulations of the RT instability are performed using FLASH in planar and cylindrical geometries to explore fundamental Rayleigh-Taylor instability evolution for these two different geometries. These geometries provide easier access for experimental diagnostics to probe RT dynamics. Additionally, the impact of externally applied magnetic fields are explored in an effort to examine if and how the detrimental instability can be controlled.
Villamizar, Avendaño Juan Manuel. « Evaluación del rendimiento de la biopsia con fusión cognitiva en el diagnóstico del Cáncer de Próstata ». Doctoral thesis, Universitat Autònoma de Barcelona, 2021. http://hdl.handle.net/10803/673202.
Texte intégralObjetivos: evaluar la eficacia de la biopsia transrectal de próstata por fusión cognitiva (BTRP-fc) en el diagnóstico del cáncer de próstata (CaP) y cáncer de próstata clínicamente significativo (CaPs). Material y métodos: análisis retrospectivo de 111 pacientes sometidos a BTRP-fc en el Hospital Verge de la Cinta entre 2014 y 2018 con lesiones PIRADS ≥ 3. Resultados: se detectaron 38 CaP (34,4%) y 25 CaPs (65,8% de todos los CaP). Se evidenciaron diferencias estadísticamente significativas favoreciendo el grupo de biopsia positiva versus negativa al estudiar las variables: edad (media de 69,84 años), PIRADS (categoría PIRADS 4), tamaño de la lesión índice (media de 16 mm) y ubicación de la lesión índice por zonas anatómicas (predominando las lesiones en la zona periférica con un 65,8%). El análisis multivariante reveló que la edad igual o superior a 70 años y el tamaño de la lesión índice igual o superior a 12 mm estaban asociados de manera independiente a un aumento de riesgo de biopsia de próstata positiva para cualquier tipo de cáncer de próstata. Conclusiones: nuestros resultados son prometedores en el marco del modelo actual de diagnóstico de cáncer de próstata que pretende detectar la enfermedad clínicamente significativa y disminuir el sobrediagnóstico y sobretratamiento de la enfermedad indolente y probablemente optimizando la estrategia de biopsia y minimizando la heterogeneidad de los métodos pudieran alcanzarse tasas de detección de CaPs aún mayores.
Objectives: to evaluate the efficacy of the cognitive fusion transrectal biopsy of the prostate (BTRP-fc) in the diagnosis of prostate cancer (CaP) and clinically significant prostate cancer (CaPs). Material and methods: retrospective analysis of 111 patients undergoing BTRP-fc at the Hospital Verge de la Cinta between 2014 and 2018 with PIRADS lesions ≥ 3. Results: 38 CaP (34.4%) and 25 CaPs (65.8% of all CaP) were detected. Statistically significant differences were observed favoring the positive versus negative biopsy group when studying the variables: age (mean 69.84 years), PIRADS (PIRADS category 4), size of the index lesion (mean 16 mm) and location of the Index lesion by anatomical areas (predominantly lesions in the peripheral zone with 65.8%). Multivariate analysis revealed that age equal to or greater than 70 years and index lesion size equal to or greater than 12 mm were independently associated with an increased risk of a positive prostate biopsy for any type of prostate cancer. Conclusions: our results are promising in the framework of the current prostate cancer diagnosis model that aims to detect clinically significant disease and reduce overdiagnosis and overtreatment of indolent disease and probably optimizing the biopsy strategy and minimizing the heterogeneity of the methods could even higher CaPs detection rates can be achieved.
Universitat Autònoma de Barcelona. Programa de Doctorat en Cirurgia i Ciències Morfològiques
Hussain, Asad. « Synergistic effects of neutrons and plasma on materials in fusion reactors & ; relaxation of merging magnetic flux ropes in fusion and solar plasmas ». Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/synergistic-effects-of-neutrons-and-plasma-on-materials-in-fusion-reactors--relaxation-of-merging-magnetic-flux-ropes-in-fusion-and-solar-plasmas(9802cf3f-f977-460c-9e9d-314e9c0e8bd5).html.
Texte intégralPeterson, Joshua T. Knowlton S. F. « Vacuum magnetic flux surface measurements made on the compact toroidal hybrid ». Auburn, Ala., 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SUMMER/Physics/Dissertation/Peterson_Joshua_48.pdf.
Texte intégralFridström, Richard. « Resonant magnetic perturbation effect on the tearing mode dynamics : Novel measurements and modeling of magnetic fluctuation induced momentum transport in the reversed-field pinch ». Doctoral thesis, KTH, Fusionsplasmafysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-218052.
Texte intégralQC 20171122
Hilscher, Paul Peter. « Study of multi-scale interaction and dissipation based on gyro-kinetic model in fusion plasmas ». Kyoto University, 2013. http://hdl.handle.net/2433/180447.
Texte intégralSheeba, Roshin Raj. « Synthetic diagnostics for plasma spectroscopy of magnetic fusion devices ». Thesis, Aix-Marseille, 2019. http://theses.univ-amu.fr.lama.univ-amu.fr/201217_SHEEBA_753c513mttwj498soje466ehx_TH.pdf.
Texte intégralIn this thesis, a numerical tool is elaborated by combining a Stark lineshape code with another code developed for the calculation of the recombination continuum due to bound-free and free-free transitions. The tool is intended to model whole Balmer spectra emitted by hydrogen or deuterium atoms for tokamak divertor plasma conditions with a focus on recombining plasmas (detachment regime). In addition to Stark line broadening, the plasma environment affects hydrogen atoms by lowering the ionization potential leading to the advance of the continuum. For hydrogen emission, these statistical plasma effects are retained using the dissolution factor approach which allows the modeling of the gradual line merging into the continuum. In this approach, bound levels are considered as free levels beyond a critical level depending on the plasma parameters. The approach is implemented by extending the continuum beyond the theoretical series limit and transforming bound levels to free ones. For simplicity, beyonf the Inglis-Teller limit, the profiles of the Balmer lines are extrapolated from that of the last resolved line. For low electron densities, the line intensities are calculated using a collisional-radiative model. The numerical tool was checked by comparison with an experimental spectrum from literature. The numerical tool was applied to predict synthetic spectra for WEST using spatial distributions of the hydrogen density and of the plasma parameters simulated along viewing chords by the transport code SOLEDGE2D-EIRENE. This approach of synthetic diagnostics of plasma spectroscopy, can easily be extended for efficient predictions for future fusion devices like ITER and DEMO
Sanabria, Edgar Rodolfo Rondán. « "Teoria e modelamento computacional de aquecimento de plasma por ondas de alfvén no tokamak TCABR" ». Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-20102006-111511/.
Texte intégralIn this work we present the study of the determination the best regimes and parameters¶for the heating experiments and current generation and plasma flow in the tokamak TCABR. Study of effects of plasma rotation in low frequency (LF), field penetration, absorption and ponderomotive forces in Tokamak Chauffage Alfvén Brésilien (TCABR)is investigated with emphasis in the frequency range of 0, 510, 0kHz. The fields of LF are driven by the ergodic magnetic limiter (EML) in TCABR. A qualitative analytical study of the Alfvén waves and their resonances is performed using simple models. A numeric study was carried out using through three codes, called the kinetic totoidal code, the cylindrical code and the ALTOK code.
Gallo, Alberto. « Impact of the plasma geometry on the divertor power exhaust in a magnetic fusion reactor ». Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0001/document.
Texte intégralA deep understanding of plasma transport at the edge of a magnetically confined fusion device is mandatory for a sustainable and controlled handling of the power exhaust. In the next-generation fusion device ITER, technological limits constrain the peak heat flux on the divertor. For a given exhaust power the peak heat flux is determined by the extent of the plasma footprint on the wall. Heat flux profiles at the divertor targets of X-point configurations can be parametrized by using two length scales for the transport of heat in SOL. In this work, we challenge the current interpretation of these two length scales by studying the impact of divertor geometry modifications on the heat exhaust. In particular, a significant broadening of the heat flux profiles at the outer divertor target is diagnosed while increasing the length of the outer divertor leg. Modelling efforts showed that diffusive simulations well reproduce the experimental heat flux profiles for short-legged plasmas. Conversely, the broadening of the heat flux for a long divertor leg is reproduced by a turbulent model, highlighting the importance of turbulent transport not only in the main SOL but also in the divertor. These results question the current interpretation of the heat flux width as a purely main SOL transport length scale. In fact, long divertor leg magnetic configurations highlighted the importance of asymmetric divertor transport. We therefore conclude that main SOL and divertor SOL transport cannot be arbitrarily disentangled and we underline the importance of the divertor magnetic geometry in enhancing asymmetric turbulent transport with the potential benefit of an unexpected power spreading
Abdelall, Fahd Fathi. « Experimental and numerical studies of the Rayleigh-Taylor instability for bounded liquid films with injection through the boundary ». Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-04072004-102937/unrestricted/abdelall%5Ffahd%5Ff%5F200405%5Fphd.pdf.
Texte intégralCosta, José Tarcisio. « Éléments finis stabilisés VMS appliqués aux modèles magnétohydrodynamiques (MHD) des plasmas de fusion ». Thesis, Université Côte d'Azur (ComUE), 2016. http://www.theses.fr/2016AZUR4117/document.
Texte intégralThe main objective of this thesis concerns the implementation of a robuststabilized finite element method for simulating fusion plasmas. For that, we firstderive the magnetohydrodynamic models from the kinetic model. MHD modelsare generally used for macroscopic simulations of plasma instabilities. Weconcentrate ou efforts on the full MHD model. Next, the numerical approach isdescribed in the context of the Variational Multi-Scale (VMS) stabilization. Thisstabilization comes to add a term to the weak formulation to mimics the effectsof the unresolved scales over the coarse scales. If the effects of these subscalesare not taken into account when dealing with fluxes dominated byconvection, as it is the cases for fusion plasmas, the numerical scheme canlead to unphysical results. A detailed study of the resistive internal kinkinstability has been done as well as an introductory study of the so called Xpointplasmas in order to validate the numerical scheme developed here
González-Villà, Sandra. « Automated brain structure segmentation in magnetic resonance images of multiple sclerosis patients ». Doctoral thesis, Universitat de Girona, 2019. http://hdl.handle.net/10803/667616.
Texte intégralAquesta tesi se centra en la segmentació automàtica de les estructures cerebrals en imatges de ressonància magnètica, aplicada a pacients d’esclerosi múltiple. Aquesta malaltia es caracteritza per la presència de lesions, que afecten els resultats de segmentació dels mètodes automàtics tradicionals. Per aquest motiu proposem un nou model de cerca de correspondències capaç de minimitzar aquest problema i estenem la teoria de dues estratègies notables de la literatura, Non-local Spatial STAPLE i Joint Label Fusion, per integrar aquest model en els seus corresponents algoritmes d’estimació. Amb l’objectiu de proporcionar algoritmes totalment automatitzats, es presenta una pipeline completa. Finalment, també es proposa una segona extensió de la teoria per permetre la integració d’anotacions manuals i automàtiques en les dues estratègies. L’anàlisi dels resultats obtinguts demostra una millora en el rendiment dels algorismes de segmentació en les àrees de lesió, que també es veu reflectida en la segmentació de tot el cervell
Addab, Younes. « Formation, caractérisation et bombardements ioniques de films minces de WO3 d'intérêt pour la fusion magnétique ». Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4765/document.
Texte intégralAs part of laboratory studies devoted to magnetic fusion we have investigated the thermal stability and the effects of helium and deuterium plasma irradiation on tungsten oxide thin films. The objective is to predict the consequences of the oxidation of the W plasma facing component (divertor) for plasma wall interactions.To this aim, we have synthesized WO3 films by thermal oxidation of W substrates at 400°C and we have characterized the effects of the W substrate, the oxygen pressure and the oxidation duration on the structure and the thickness of the oxide films. The sample crystalline structure (monoclinic nanocrystalline), defects and morphologies were characterized before and after treatment using scanning and transmission electron microscopies, Raman microscopy, X-Ray diffraction and atomic force microscopy. Heating under vacuum up to 800°C leads to changes in the film structure and composition which results in the formation of WO2. D+ bombardment (11 eV) leads to D+ diffusion throughout the oxide film and to an electrochromic effect, here observed for the first time under plasma irradiation. This effect - which turned out to be reversible - is related to the formation of W bronzes (DxWO3) and to a phase transition of the oxide toward a hexagonal structure. Helium bombardments (20 eV) have then been performed to unravel physical and chemical processes at play. He+ bombardment at room temperature causes slight structural and morphological changes. On the contrary, He+ bombardment at 400°C leads to a significant erosion of the oxide film, accompanied by a colour change, the surface amorphisation and the formation of bubbles at the W / WO3 interface
Heideklang, René. « Data Fusion for Multi-Sensor Nondestructive Detection of Surface Cracks in Ferromagnetic Materials ». Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19586.
Texte intégralFatigue cracking is a dangerous and cost-intensive phenomenon that requires early detection. But at high test sensitivity, the abundance of false indications limits the reliability of conventional materials testing. This thesis exploits the diversity of physical principles that different nondestructive surface inspection methods offer, by applying data fusion techniques to increase the reliability of defect detection. The first main contribution are novel approaches for the fusion of NDT images. These surface scans are obtained from state-of-the-art inspection procedures in Eddy Current Testing, Thermal Testing and Magnetic Flux Leakage Testing. The implemented image fusion strategy demonstrates that simple algebraic fusion rules are sufficient for high performance, given adequate signal normalization. Data fusion reduces the rate of false positives is reduced by a factor of six over the best individual sensor at a 10 μm deep groove. Moreover, the utility of state-of-the-art image representations, like the Shearlet domain, are explored. However, the theoretical advantages of such directional transforms are not attained in practice with the given data. Nevertheless, the benefit of fusion over single-sensor inspection is confirmed a second time. Furthermore, this work proposes novel techniques for fusion at a high level of signal abstraction. A kernel-based approach is introduced to integrate spatially scattered detection hypotheses. This method explicitly deals with registration errors that are unavoidable in practice. Surface discontinuities as shallow as 30 μm are reliably found by fusion, whereas the best individual sensor requires depths of 40–50 μm for successful detection. The experiment is replicated on a similar second test specimen. Practical guidelines are given at the end of the thesis, and the need for a data sharing initiative is stressed to promote future research on this topic.
Burrell, Lauren S. « Feature analysis of functional mri data for mapping epileptic networks ». Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26528.
Texte intégralTaccon, Cristiano. « Iter di magnetic diagnostics : design study of in-vessel electro-magnetic sensors ». Doctoral thesis, Università degli studi di Padova, 2008. http://hdl.handle.net/11577/3426384.
Texte intégralAHMAD, ALI. « Study of impulsive magnetic reconnection due to resistive tearing mode with the effect of viscosity and dynamic flow in fusion plasmas ». Kyoto University, 2015. http://hdl.handle.net/2433/199415.
Texte intégralBorkowetz, Angelika, Ivan Platzek, Marieta Toma, Theresa Renner, Roman Herout, Martin Baunacke, Michael Laniado et al. « Evaluation of Magnetic Resonance Imaging/ Ultrasound-Fusion Biopsy in Patients with Low-Risk Prostate Cancer Under Active Surveillance Undergoing Surveillance Biopsy ». Karger, 2018. https://tud.qucosa.de/id/qucosa%3A70640.
Texte intégralSommariva, Cristian. « Test particles dynamics in 3D non-linear magnetohydrodynamics simulations and application to runaway electron formation in tokamak disruptions ». Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0512/document.
Texte intégralIn view of better understanding Runaway Electron (RE) generation processes during tokamak disruptions, this work investigates test electron dynamics during a JET disruption simulated with the JOREK code. For this purpose, a JOREK module computing relativistic test particle orbits in the simulated fields has been developed and tested. The study shows that a significant fraction of pre-disruption thermal electrons remain confined in spite of the magnetic chaos characterizing the Thermal Quench (TQ) phase. This finding, which is related to the prompt reformation of closed flux surfaces after the TQ, supports the possibility of the so-called “hot tail” RE generation mechanism. In addition, it is found that electrons may be significantly accelerated during the TQ due to the presence of strong local electric field (E) fluctuations related to magnetohydrodynamic (MHD) activity. This phenomenon, which has virtually been ignored so far, may play an important role in RE generation. In connection to this modelling work, an experimental study on ASDEX Upgrade disruptions has been performed, suggesting that strong MHD activity reduces RE production
Makni, Aida. « Fusion de données inertielles et magnétiques pour l’estimation de l’attitude sous contrainte énergétique d’un corps rigide accéléré ». Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAT025/document.
Texte intégralIn this PhD. thesis we deal with attitude estimation of accelerated rigid body moving in the 3D space using quaternion parameterization. This problem has been widely studied in the literature in various application areas. The main objective of the thesis is to propose new methods for data fusion to combine inertial gyros) and magnetic measurements. The first challenge concerns the attitude estimation during dynamic cases, in which external acceleration of the body is not negligible compared to the Gravity. Two main approaches are proposed in this context. Firstly, a quatenion-based adaptive Kalman filter (q-AKF) was designed in order to compensate for such external acceleration. Precisely, a smart detector is designed to decide whether the body is in static or dynamic case. Then, the covariance matrix of the external acceleration is estimated to tune the filter gain. Second, we developed descriptor filter based on a new formulation of the dynamic model where the process model is fed by accelerometer measurements while observation model is fed by gyros and magnetometer measurements. Such modeling gives rise to a descriptor system. The resulting model allows taking the external acceleration of the body into account in a very efficient way. The second challenge is related to the energy consumption issue of gyroscope, considered as the most power consuming sensor. We study the way to reduce the gyro measurements acquisition by switching on/off the sensor while maintaining an acceptable attitude estimation. The effciency of the proposed methods is evaluated by means of numerical simulations and experimental tests
Beaucourt-Jacquet, Céline. « Étude expérimentale du guidage du faisceau d’électrons dans le cadre de l’allumage rapide de cibles de fusion ». Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14741/document.
Texte intégralThe work presented in this thesis is realised in the framework of the fast ignition of inertial confinement fusion for energy production. In this scheme the compression and the ignition phases are decoupled. During the second phase, the electron beam must cross over 300 µm in the dense fuel to deposit its energy in the dense core and ignite the fusion reactions.The major problem of the scheme is related to the divergence of the electron beam while it crosses the dense matter. Among the different propositions to inhibit the electron divergence we consider here the schemes without cone that are based on the effect of magnetic collimation. In particular, A.P.L. Robinson and his co-authors [Phys. Rev. Lett. 100, 025002, 2008] suggested a simple way to control the electron beam divergence by using a sequence of two laser pulses. The first one creates a magnetic background favourable for the confinement of the second electron beam resulting from the second interaction. The validation of this scheme is the major goal of this thesis.We present the results of experimental sudies and numerical modeling of the electron beam guiding with help of two consequent laser pulses. The experiment was performed on the Vulcan facility at the Rutherford Appleton Laboratory at Didcot in UK, based on the proposal submitted by an international group of scientists in the framework of the European project for inertial fusion energy HiPER. This experiment allowed us to define a combination of laser and target parameters where the electron beam guiding takes place. The analysis of experimental data and numerical modelling is realised with the hydrodynamic code CHIC coupled to the charged particules transport module M1. The interpretation of the experimental results allowed us to explain the experimental data and the physical basis of guiding and to define the magnetic conditionflavourable to the electron beam guidance
Ivanova, Darya. « Plasma-Facing Components in Tokamaks : Material Modification and Fuel Retention ». Doctoral thesis, KTH, Fusionsplasmafysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105099.
Texte intégralQC 20121116
Woestenenk, Esmeralda A. « Protein production, characterization and structure determination in structural genomics ». Doctoral thesis, KTH, Biotechnology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-29.
Texte intégralThis thesis covers the process from expression of a heterologous gene in Escherichia coli to structure determination of a protein by nuclear magnetic resonance (NMR) spectroscopy.
The first part concerns structural genomics-related parallel screening studies on the effect of fusion tags (in particular the His tag) on protein solubility and the use of fusion tags in fast, parallel purification protocols intended for initial biophysical characterization of human proteins produced in E. coli. It was found that for most proteins the His tag has a negative influence on protein solubility. This influence appears to be more pronounced for our C-terminal His tag than for the N-terminal His tags used in this study. Moreover, high ratios of soluble per total protein do not always guarantee a high yield of soluble protein after purification, as different vector - target protein combinations result in large differences in host cell growth rates. Protein purification protocols for different fusion tags were developed that make it possible to express, purify and study structural properties of low concentration samples of 15N-labeled proteins in one or two days.
The second part of this thesis describes the assignment and solution structure determination of ribosomal protein L18 of Thermus thermophilus. The protein is a mixed α/β structure with two α-helices on one side of a four-stranded β-sheet. Comparison to RNA-bound L18 showed that the protein to a large extent adopts identical structures in free and bound states, with exception of the loop regions and the flexible N-terminus.
Keywords: protein production, protein solubility, fusion tags, nuclear magnetic resonance, structure determination, ribosomal protein
Gonzalez, Winder Alexander. « Study, development and analysis of In-vessel pick-up coil sensors for ITER magnetic diagnostic and n & ; gamma detection in fusion plasmas ». Doctoral thesis, Università degli studi di Padova, 2014. http://hdl.handle.net/11577/3424759.
Texte intégralIl lavoro di ricerca descritto in questa tesi è stato dedicato al tema della diagnostica magnetica per ITER e alla rivelazione dei neutroni e dei raggi gamma nell'esperimento RFX-mod. L'obiettivo principale è stato il disegno di un nuovo concetto di bobine pick-up, basate sulla tecnologia Low-Temperature Co-fired Ceramic (LTCC), che è stata proposta nella fase concettuale del disegno per il sistema diagnostico magnetico di vuoto di ITER. Il disegno, nella fase preliminare è stato sviluppato nell'ambito di una collaborazione internazionale, diretta dal consorzio RFX e finanziata dall'agenzia europea Fusion for Energy (F4E) e dall'organizzazione ITER. Le attività realizzate durante il periodo di dottorato si sono concentrate sui vari aspetti del disegno dei sistemi di diagnostico in plasma, come l'analisi termico-meccanica, l'interazione neutronica, il disegno dei sistemi di vuoto e le prove termoelettriche in sensori prototipo. Nella fase finale del dottorato le abilità e conoscenze acquisite sono state applicate all'installazione e all'operazione di un sistema per la rivelazione di neutroni e fotoni in RFX-mod. I risultati più importanti ottenuti nei diversi argomenti studiati sono descritti nei seguenti capitoli: Parte teorica e contesto della tesi (Capitoli 1, 2 e 3): In questi capitoli, dopo una descrizione basilare della fusione nucleare, le basi teoriche e gli argomenti principali che hanno motivato questa ricerca sono descritti, con un'enfasi specifica sulla diagnostica magnetica. Lo studio riportato in questa parte è supportato dalla consultazione di una estesa letteratura riguardo ai lavori teorici e tecnici realizzati precedentemente nel disegno e nello sviluppo di bobine magnetiche basate sulla tecnologia LTCC, che ha condotto al disegno di un nuovo gruppo di prototipi, migliorati per soddisfare i requisiti di ITER. Caratterizzazione dei sensori prototipo (Capitolo 4): Questo capitolo descrive una serie di prove per la caratterizzazione dei sensori prototipo, sviluppati con lo scopo di elaborare un disegno dettagliato per il sistema magnetico di ITER. Per raggiungere questo obiettivo si è creato un protocollo formale delle prove necessarie per la caratterizzazione totale dei sensori. Nello specifico, queste prove sono state concentrate sull'analisi della planarità, delle dimensioni fisiche, delle caratteristiche elettriche magnetiche e termoelettriche di quaranta sensori prototipo (terza generazione). Compatibilità con vuoto (Capitolo 5): In questo capitolo sono descritti i principali poblemi legati alla compatibilità dei componenti in vuoto, come nel caso dei sensori magnetici. `E avanzata una proposta di disegno di un sistema di prova per la misurazione del degasamento. Viene presentata inoltre una dettagliata descrizione del sistema in CAD, e la stima del costo. Assemblaggio meccanico del sensore (Capitolo 6): In questo capitolo vengono descritti gli aspetti legati all'analisi termomeccanica del supporto del sensore dentro la camera di vuoto di ITER. Vari argomenti sono stati studiati con adeguate simulazioni FEM. Per prima cosa si è valutato il gradiente di temperatura dentro il corpo del sensore, per minimizzare la misurazione del rumore di fondo dovuto alla sensibilità termica; in seguito si è ottimizzato lo stress indotto dalla saldatura; infine si è studiata la fattibilità tecnica dell'applicazione dei metodi per saldatura delle connessioni elettriche del sensore. Simulazioni dei sensori LTCC sotto radiazione neutronica (Capitolo 7): Questo capitolo è dedicato alla valutazione della potenza nucleare indotta [W/cm^3 ] dalle interazioni neutroniche dentro il sensore LTCC, considerando un gruppo di spettri neutronici [n/cm^2 /s] tipico del blanket di ITER. Questo studio consiste nella realizzazione di una serie di simulazioni di interazione neutronica, basate sul metodo Monte Carlo, utilizzando un modello dettagliato del sensore e due potenziali ubicazioni per l'installazione. RFX-mod come fonte di neutroni e raggi gamma (Capitolo 8): Questo capitolo riassume le attività realizzate durante l'installazione e l'operazione di due rivelatori a scintillio (Nal Scintillator e NE213 Liquid Scitillator) nel periodo della sessione sperimentale (gennaio-settembre 2014) di RFX-mod. Questo esperimento rappresenta la fase iniziale nella rivelazione dei neutroni e nella produzione di fotoni in plasma di deuterio in RFX-mod. Un totale di 1185 impulsi sono stati analizzati nei sette mesi di sessione sperimentale: è stato misurato il fondo di emissione neutronica, si è discusso il blindaggio magnetico e sono stati inoltre studiati e documentati problemi di calibrazione e acquisizione dei dati
Bailly-Grandvaux, Mathieu. « Laser-driven strong magnetic fields and high discharge currents : measurements and applications to charged particle transport ». Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0557/document.
Texte intégralThe problem of strong quasi-static magnetic field generation is a challenge in laser-plasma interaction physics. Proposed 30 years ago, the use of the laser-driven capacitor-coil scheme, which stands out for its compact design while not needing any additional pulsed power source besides the laser power, only recently demonstrated its potential.This thesis work aims at characterizing the underlying physics and at developing this scheme. We demonstrated the generation of strong quasi-static magnetic fields by laser (500 J, 1 ns-duration and ~10^17 W/cm^2 intensity) of several hundreds of Teslas and duration of 2-3 ns. The B-field space- and time-evolutions were characterized using three independent diagnostics: B-dot probes, Faraday rotation and proton-deflectometry). The characterization of the underlying physical processes involved also X-ray diagnostics of the laser-irradiated zone and optical shadowgraphy of the coil rod expansion.A novel application of externally applied magnetic fields to guide relativistic electron beam in dense matter has been carried out and the obtained results set the ground for improved high-energy-density transport in matter. Indeed, allowing sufficient time for the dense target magnetization, a factor 5 improvement of the electron energy-density flux at 50µm-depth was evidenced.Besides, the generation of high discharge currents consecutive to short laser pulse irradiation (50 J, <1 ps-duration and ~10^19 W/cm^2 intensity) was also pointed out. Proton imaging of the discharge permitted to measure the propagation of an electromagnetic wave at a velocity close to the speed of light. This wave, of ~40ps-duration, was used as an electromagnetic lens to focalize and energy-select a narrow energy range within a multi-MeV proton beam (up to 12 MeV) passing through the coil.All-above experimental measurements and application results were thoroughly compared to both computer simulations and analytic modeling.The applications of this thesis work in a near future will concern:- inertial confinement fusion, by guiding relativistic electron beams up to the dense core nuclear fuel, and by confining particles depositing their energy in it, or even those resulting from the fusion reactions;- laboratory planetology and astrophysics, by generating secondary sources of energetic particles and radiation to reach the warm-dense-matter state or by magnetizing plasmas to reproduce astrophysical phenomena in scaled experiments;- and finally, the control of charged particle beams in vacuum, useful in particular for the development of laser-driven sources for distant applications in science, industry or even medecine
Borkowetz, Angelika, Theresa Renner, Ivan Platzek, Marieta Toma, Roman Herout, Martin Baunacke, Christer Groeben et al. « Evaluation of Transperineal Magnetic Resonance Imaging/Ultrasound-Fusion Biopsy Compared to Transrectal Systematic Biopsy in the Prediction of Tumour Aggressiveness in Patients with Previously Negative Biopsy ». Karger, 2018. https://tud.qucosa.de/id/qucosa%3A71674.
Texte intégralForshed, Jenny. « Processing and analysis of NMR data : Impurity determination and metabolic profiling ». Doctoral thesis, Stockholm : Dept. of analytical chemistry, Stockholm university, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-712.
Texte intégralOlofsson, K. Erik J. « Nonaxisymmetric experimental modal analysis and control of resistive wall MHD in RFPs : System identification and feedback control for the reversed-field pinch ». Doctoral thesis, KTH, Fusionsplasmafysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-94096.
Texte intégralQC 20120508
Floyd, John-Patrick. « Evolution of edge pedestal transport between ELMs in DIII-D ». Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53079.
Texte intégralSener, Emre. « Automatic Bayesian Segmentation Of Human Facial Tissue Using 3d Mr-ct Fusion By Incorporating Models Of Measurement Blurring, Noise And Partial Volume ». Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615091/index.pdf.
Texte intégralNgadjeu, Djomzoue Alain narcisse. « Etude des effets de gaine induites par une antenne de chauffage à la fréquence cyclotronique ionique (FCI, 30-80 MHz) et de leur impact sur les mesures par sondes dans les plasmas de fusion ». Thesis, Nancy 1, 2010. http://www.theses.fr/2010NAN10118/document.
Texte intégralThis work investigates the problematic of probe measurements in RF environment. DC currents flowing along magnetic field lines connected to powered ICRF antennas have been observed experimentally. Negative (i.e. net electron) current is collected on the powered ICRF antenna structure, while positive (i.e. net ion) current is collected by magnetically connected Langmuir probes. An asymmetric model based upon a double probe configuration was developed. The ICRF near field effect is mimicked by a ?driven? RF electrode at one extremity of an "active" open magnetic flux tube, where a purely sinusoidal potential is imposed. The other connection point is maintained at ground potential to model a collecting probe. This "active" flux tube can exchange transverse RF currents with surrounding "passive" tubes, whose extremities are grounded. With simple assumptions, an analytical solution is obtained. We can thus explain how DC currents are produced from RF sheaths. This model also makes it possible to model the characteristics DC Current' DC Voltage of a probe in the presence of RF and thus to evaluate some plasma properties. In this case the electrode at ground potential (probe) is polarized at a given potential. Analytical results are found within certain limits
Riquier, Raphaël. « Magnetic field in laser plasmas : non-local electron transport and reconnection ». Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX004/document.
Texte intégralIn the framework of the inertial confinement fusion, a pellet filled with the deuterium-tritium fuel is imploded, either through laser irradiation (direct drive, laser – low atomic number target interaction) or by the black body radiation from a cavity converting the laser radiation (indirect drive, laser – high atomic number target interaction).In both cases, a correct modeling of the electron transport is of first importance in order to have predictive hydro-radiative simulations. Nonetheless, it has been shown early on that the hypothesis of the linear transport are not valid in the framework of a solid target irradiated by a high power laser (I~1014 W/cm²). This is due in part to very steep temperature gradients (kinetic effects, so-called « non-local ») and because of a magnetic field self-generated through the thermo-electric effect. Finally, the heat flux and the magnetic field are strongly coupled through two mecanisms: the advection of the field with the heat flux (Nernst effect) and the rotation and inhibition of the heat flux by the plasma's magnetization (Righi-Leduc effect).In this manuscript, we will first present the various electron transport models, particularly the non-local with magnetic field model included in the hydro-radiative code FCI2. Following, in order to validate this model, we will compare it first against a kinetic code, and then with an experiment during which the magnetic field has been probed through proton radiography. Once the model validated, we will use FCI2 simulations to explain the source and transport of the field, as well as its effect on the interaction.Finally, the reconnection of the magnetic field, during the irradiation of a solid target by two laser beams, will be studied