Log in

Relevant bibliographies by topics / Paschen's Law / Journal articles

Journal articles on the topic 'Paschen's Law'

To see the other types of publications on this topic, follow the link: Paschen's Law.

Author: Grafiati

Published: 10 December 2022

Last updated: 29 January 2023

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 46 journal articles for your research on the topic 'Paschen's Law.'

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 journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Massarczyk, R., P. Chu, C. Dugger, S. R. Elliott, K. Rielage, and W. Xu. "Paschen's law studies in cold gases." Journal of Instrumentation 12, no. 06 (June 27, 2017): P06019. http://dx.doi.org/10.1088/1748-0221/12/06/p06019.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

McAllister, I. W., and G. C. Crichton. "The concept of Paschen's law with reference to SF6." Journal of Physics D: Applied Physics 20, no. 11 (November 14, 1987): 1537–39. http://dx.doi.org/10.1088/0022-3727/20/11/027.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Berger, G., and B. Senouci. "The role of impurities on the deviation from Paschen's law of SF6." Journal of Physics D: Applied Physics 19, no. 12 (December 14, 1986): 2337–42. http://dx.doi.org/10.1088/0022-3727/19/12/013.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Mellinger, Axel, and Olena Mellinger. "Breakdown threshold of dielectric barrier discharges in ferroelectrets: where Paschen's law fails." IEEE Transactions on Dielectrics and Electrical Insulation 18, no. 1 (February 2011): 43–48. http://dx.doi.org/10.1109/tdei.2011.5704491.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Kim, S. J. "Gas sensors based on Paschen's law using carbon nanotubes as electron emitters." Journal of Physics D: Applied Physics 39, no. 14 (June 30, 2006): 3026–29. http://dx.doi.org/10.1088/0022-3727/39/14/022.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Loveless, Amanda M., Adam M. Darr, and Allen L. Garner. "Linkage of electron emission and breakdown mechanism theories from quantum scales to Paschen's law." Physics of Plasmas 28, no. 4 (April 2021): 042110. http://dx.doi.org/10.1063/5.0040633.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Spyrou, N., R. Peyrous, N. Soulem, and B. Held. "Why Paschen's law does not apply in low-pressure gas discharges with inhomogeneous fields." Journal of Physics D: Applied Physics 28, no. 4 (April 14, 1995): 701–10. http://dx.doi.org/10.1088/0022-3727/28/4/013.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

KIM, SEONGJEEN. "DETECTION OF INERT GASES BY COLD ELECTRON EMISSION FROM CARBON NANOTUBE EMITTERS." Modern Physics Letters B 19, no. 24 (October 30, 2005): 1207–11. http://dx.doi.org/10.1142/s0217984905009304.

Full text

Abstract:

In this work, different from the typical gas sensors responding by gas adsorption on their surface, a new gas sensor using carbon nanotubes (CNTs) as electron emitters is introduced for detecting inert gases which hardly possess chemical or electrical adsorption in normal conditions. The proposed sensor works by figuring out the variation of the dark current and the initial breakdown voltage on Paschen's law under applied high voltage. As they depend on the gas composition and the pressure in a sealed chamber, it is possible to detect the identity and the concentration of unknown inert gas species.

APA, Harvard, Vancouver, ISO, and other styles

9

Medvedev D.D., Belov N.K., Grankina O.O., Knizhnik A.A., Korobtsev S.V., and Potapkin B.V. "Investigation of the conditions for gas breakdown in a porous dielectric." Technical Physics Letters 48, no. 13 (2022): 79. http://dx.doi.org/10.21883/tpl.2022.13.53371.18914.

Full text

Abstract:

Plasma treatment of porous polymeric materials is a promising method for creating new materials that can be used in various applied problems, including medicine, in the development of new types of biocompatible and biodegradable polymeric materials. This work is devoted to the study of the processes of plasma treatment of porous polymeric materials depending on the size and type of pores in order to clarify the breakdown conditions and optimize the treatment process. A convenient semi-empirical model of the development of breakdown in a porous dielectric is proposed. Keywords: plasma treatment of a dielectric, Paschen's law in a porous medium, breakdown voltage of a porous material.

APA, Harvard, Vancouver, ISO, and other styles

10

Zhou, Jianchi, Yingjie Gan, Hang Jin, and David Pommerenke. "ESD Spark Behavior and Modeling for Geometries Having Spark Lengths Greater Than the Value Predicted by Paschen's Law." IEEE Transactions on Electromagnetic Compatibility 60, no. 1 (February 2018): 115–21. http://dx.doi.org/10.1109/temc.2017.2704607.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Peschot, A., N. Bonifaci, O. Lesaint, C. Valadares, and C. Poulain. "Deviations from the Paschen's law at short gap distances from 100 nm to 10 μm in air and nitrogen." Applied Physics Letters 105, no. 12 (September 22, 2014): 123109. http://dx.doi.org/10.1063/1.4895630.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Chen, Jiandong, John P. Verboncoeur, and Yangyang Fu. "Microgap breakdown with floating metal rod perturbations." Applied Physics Letters 121, no. 7 (August 15, 2022): 074102. http://dx.doi.org/10.1063/5.0104205.

Full text

Abstract:

We report the characterization of microgap breakdown with perturbations from a metal rod floating between anode and cathode electrodes. The effects of the metal rod on the electric field distribution and the field enhancement factor are evaluated by numerical simulation and the conformal mapping method, and they indicate that the field emission regime is not reached. The breakdown voltages in the Townsend discharge regime are determined based on the voltage–current characteristics, which are obtained from two-dimensional fluid simulations. It is found that the breakdown characteristics can be significantly modulated by the floating metal rod, and the breakdown curve (breakdown voltage vs the net gap distance) is no longer U-shaped, which deviates from the conventional Paschen's law. The underlying physical mechanisms are related to the electric field enhancement, curved breakdown path, and nonuniform ion flux caused by the electric shielding effect. The results provide insights into breakdown characteristics in microscale discharges, which may promote conventional investigation of simplified clean gaps toward more complex conditions (e.g., with floating microparticles) in miniaturized plasma devices.

APA, Harvard, Vancouver, ISO, and other styles

13

Al-Hakary, Shamo Kh, Esraa A. Mohammed Saeed, Diyar A. Bleej, Suzan M. Haji, and Sahme A. Hussain. "Studing of Some Characteristics and parameters of Argon Glow discharge plasma Using Hollow Anode Diameter." Science Journal of University of Zakho 6, no. 1 (March 28, 2018): 26. http://dx.doi.org/10.25271/2018.6.1.401.

Full text

Abstract:

Hollow anode argon glow discharge plasma has been investigated experimentally at different argon gas pressure from constant discharge current. A sufficient high voltage has been applied among the electrodes to obtain breakdown. Firstly, we studied the influence of hollow anode diameter on the breakdown voltage and Paschens law. The inner diameters of hollow anodes used in our work were (10, 15, 20, 25, 30, 35, and 40) mm. Secondly under the same conditions we extended our study to measure some plasma parameters in the negative glow region using direct current argon glow discharge. The temperature and density of electrons in the negative glow were measured using double probes. From the (Ip-Vp) characteristics of double probes, we obtained plasma parameters by using computer MATLAB program. The results showed that the measured Pashence's curve closes to the well-known theoretical Pashence's law. The breakdown voltage and its minimum value decreased with increasing the hollow anode diameter. The Paschen’s curve became wide and shifted to lower pressure with increasing the diameter. The reduction area of hollow anode caused dens and luminous intensity of plasma to occur in the negative glow region. Increasing the diameter resulted in decreasing the temperature and density of electron.

APA, Harvard, Vancouver, ISO, and other styles

14

Babich, Leonid, and Tat'yana V. Loiko. "Generalized Paschen’s Law for Overvoltage Conditions." IEEE Transactions on Plasma Science 44, no. 12 (December 2016): 3243–48. http://dx.doi.org/10.1109/tps.2016.2629022.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Eichhorn, H., K. H. Schoenbach, and T. Tessnow. "Paschen’s law for a hollow cathode discharge." Applied Physics Letters 63, no. 18 (November 1993): 2481–83. http://dx.doi.org/10.1063/1.110455.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Galli, Giacomo, Hassen Hamrita, C. Jammes, Michael J. Kirkpatrick, Emmanuel Odic, Philippe Dessante, and Philippe Molinie. "Paschen’s Law in Extreme Pressure and Temperature Conditions." IEEE Transactions on Plasma Science 47, no. 3 (March 2019): 1641–47. http://dx.doi.org/10.1109/tps.2019.2896352.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Wang, Jing. "Simulation of Gas Discharge in Tube and Paschen’s Law." Optics and Photonics Journal 03, no. 02 (2013): 313–17. http://dx.doi.org/10.4236/opj.2013.32b073.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Torres, C., P. G. Reyes, F. Castillo, and H. Martínez. "Paschen law for argon glow discharge." Journal of Physics: Conference Series 370 (June 19, 2012): 012067. http://dx.doi.org/10.1088/1742-6596/370/1/012067.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Roger, Daniel, Sonia Ait-Amar, and Ewa Napieralska. "A method to reduce partial discharges in motor windings fed by PWM inverter." Open Physics 16, no. 1 (October 19, 2018): 599–604. http://dx.doi.org/10.1515/phys-2018-0078.

Full text

Abstract:

AbstractA new approach for designing ac motor windings free of partial discharges (PD) is proposed. The method consists of adding a thin conducting layer on the outer surface of the enameled wire used for building the machine winding. With this additional layer, PDs occur only in critical zones localized near the wire connections rather than randomly in the residual voids between turns. With such deterministic localizations, it is possible to reduce strongly the PD activity by adding small quantities of varnish in the determined critical zones. After studying the validity of the Paschen’s hypotheses for this application, the Paschen’s law is coupled to an electrostatic finite element analysis, for predicting the Partial Discharge Inception Voltage (PDIV), which corresponds to the electronic avalanche ignition in the air of critical zones.

APA, Harvard, Vancouver, ISO, and other styles

20

Prescott, Moire K. M., Kristian M. Finlator, Nikko J. Cleri, Jonathan R. Trump, and Casey Papovich. "Using Multiple Emission Line Ratios to Constrain the Slope of the Dust Attenuation Law." Astrophysical Journal 928, no. 1 (March 1, 2022): 71. http://dx.doi.org/10.3847/1538-4357/ac5459.

Full text

Abstract:

Abstract We explore the possibility and practical limitations of using a three-line approach to measure both the slope and normalization of the dust attenuation law in individual galaxies. To do this, we focus on a sample of 11 galaxies with existing ground-based Balmer Hα and Hβ measurements from slit spectra, plus space-based grism constraints on Paschen-β. When accounting for observational uncertainties, we show that one galaxy has a well-constrained dust-law slope and normalization in the range expected from theoretical arguments; this galaxy therefore provides an example of what may be possible in the future. However, most of the galaxies are best fit by unusually steep or shallow slopes. We then explore whether additional astrophysical effects or observational biases could explain the elevated Paschen-β/Hα ratios driving these results. We find that galaxies with high Paschen-β/Hα ratios may be explained by slightly sub-unity covering fractions (>97%). Alternatively, differing slit losses for different lines can have a large impact on the results, emphasizing the importance of measuring all three lines with a consistent spectroscopic aperture. We conclude that, while the three-line approach to constraining the shape of the dust attenuation law in individual galaxies is promising, deep observations and a consistent observational strategy will be required to minimize observational biases and to disentangle the astrophysically interesting effect of differing covering fractions. The James Webb Space Telescope will provide more sensitive measurements of Balmer and Paschen lines for galaxies at z ≈ 0.3–2, enabling uniform constraints on the optical–infrared dust attenuation law and its intrinsic variation.

APA, Harvard, Vancouver, ISO, and other styles

21

Mathew, Prijil, Jobin George, Sajith Mathews T, and P. J. Kurian. "Experimental verification of modified Paschen’s law in DC glow discharge argon plasma." AIP Advances 9, no. 2 (February 2019): 025215. http://dx.doi.org/10.1063/1.5086246.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Young, Ronald P., James L. DuBard, and Leslie E. Sparks. "The Onset of Electrical Breakdown in Dust Layers: I, Microsparking Described by Paschen’s Law." JAPCA 38, no. 11 (November 1988): 1412–18. http://dx.doi.org/10.1080/08940630.1988.10466481.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Kozyrev, A. V., V. Yu Kozhevnikov, A. O. Kokovin, and S. Y. Medvedev. "On minimum of static breakdown voltage for gas-filled gap." Izvestiya vysshikh uchebnykh zavedenii. Fizika, no. 9 (2021): 59–64. http://dx.doi.org/10.17223/00213411/64/9/59.

Full text

Abstract:

Based on the self-sustaining condition of the discharge, a theoretical analysis was carried out in order to identify the minimum possible breakdown voltage. It is shown that a weak nonuniformity of the electric field in the discharge gap leads to an increase in the static breakdown voltage in comparison with the Paschen’s law. A strong nonuniformity of the field in diodes of coaxial and spherical geometry also cannot provide a decrease in the minimum breakdown voltage in comparison with the case of a plane-parallel gap. It is proved that of all symmetric geometries of a gas-filled diode, the planar geometry has the lowest breakdown voltage.

APA, Harvard, Vancouver, ISO, and other styles

24

Radwan, Samah, H. El-Khabeary, and A. Helal. "Verification of Paschen Law using a Mixed Geometry Disc-Conical Electrodes." Journal of Engineering Science and Military Technologies 17, no. 17 (April 1, 2017): 1–10. http://dx.doi.org/10.21608/ejmtc.2017.21230.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Lee, Min Uk, Jimo Lee, Jae Koo Lee, and Gunsu S. Yun. "Extended scaling and Paschen law for micro-sized radiofrequency plasma breakdown." Plasma Sources Science and Technology 26, no. 3 (February 10, 2017): 034003. http://dx.doi.org/10.1088/1361-6595/aa52a8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Radwan, Samah, H. El-Khabeary, and A. Helal. "Verification of Paschen Law using a Mixed Geometry Disc-Conical Electrodes." International Conference on Aerospace Sciences and Aviation Technology 17, AEROSPACE SCIENCES (April 1, 2017): 1–10. http://dx.doi.org/10.21608/asat.2017.22465.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Gou, Weijie, and Lihong Wang. "Test and Analysis of TIG-MIG Hybrid Welding Are." Journal of Physics: Conference Series 2152, no. 1 (January 1, 2022): 012031. http://dx.doi.org/10.1088/1742-6596/2152/1/012031.

Full text

Abstract:

Abstract A high-speed camera is used to observe the arc starting and arc stabilization process of the TIG-MIG hybrid welding system. Paschen’s law is used to analyze the path of TIG welding arc breakdown under the condition of the conductive channel provided by the MIG welding arc, and the arc starting process of the double arc hybrid welding is determined. The study found that when the electrode spacing is less than 8.5 mm, two molten pools can form a common molten pool after arc initiation of MIG welding; when the spacing is 10 mm, the two molten pools after arc initiation form a “8” shape; When the distance is 12 mm, there is a low temperature zone between the two arcs, which is separated.

APA, Harvard, Vancouver, ISO, and other styles

28

Serdyuk, Yu V., I. V. Bozhko, and N. I. Fal’kovskii. "Electrical breakdown in nonuniformly heated gases and the upper temperature limit of the applicability of Paschen’s law." High Temperature 38, no. 3 (May 2000): 335–43. http://dx.doi.org/10.1007/bf02755988.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Waters, R. T. "Electrical breakdown at high pressures: a Paschen law function and compressible gas dynamics." Journal of Physics D: Applied Physics 52, no. 2 (November 2, 2018): 025203. http://dx.doi.org/10.1088/1361-6463/aae815.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Loveless, Amanda M., and Allen L. Garner. "A universal theory for gas breakdown from microscale to the classical Paschen law." Physics of Plasmas 24, no. 11 (November 2017): 113522. http://dx.doi.org/10.1063/1.5004654.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Lisovskii, V. A., and S. D. Yakovin. "A modified Paschen law for the initiation of a dc glow discharge in inert gases." Technical Physics 45, no. 6 (June 2000): 727–31. http://dx.doi.org/10.1134/1.1259709.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Ma, Long-Fei, Li Duan, Jian-Wu He, and Qi Kang. "The impact of neutralizer-free ignition of a radio frequency ion thruster on the lifetime of the ion optics system." International Journal of Modern Physics A 36, no. 11n12 (April 9, 2021): 2140017. http://dx.doi.org/10.1142/s0217751x21400170.

Full text

Abstract:

In the initial stage of a radio frequency ion thruster (RIT) ignition, an influx of electrons is required from an external source into the discharge chamber and ionization of the neutral gas propellant. A neutralizer-free method for Townsend breakdown discharge ignition based on Paschen’s law was developed in this study. The feasibility of the ignition method was confirmed by performing thousands of ignition experiments. Metallic Molybdenum (Mo), pyrolytic graphite (PG) and Zr[Formula: see text]Ti[Formula: see text]Cu[Formula: see text]Ni[Formula: see text]Be[Formula: see text]alloy acceleration grids were prepared, and ignition-induced damage on the grids was investigated. A field-emission scanning electron microscope was used to inspect surface damage on the grids after multiple ignitions and to analyze the influence of the ignition method on the lifetime of the ion optical system. Grid materials for space missions that require multiple RIT ignitions (10[Formula: see text] should be high-strength blocks that are resistant to sputtering corrosion and high temperature.

APA, Harvard, Vancouver, ISO, and other styles

33

Mathurin, Theo, Stephane Duchesne, and Guillaume Parent. "Assessment of Finite Element Simulation Methodologies for the Use of Paschen’s Law in the Prediction of Partial Discharge Risk in Electrical Windings." IEEE Access 8 (2020): 144557–64. http://dx.doi.org/10.1109/access.2020.3013337.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Lee, Min Uk, Jimo Lee, Jae Koo Lee, and Gunsu S. Yun. "Corrigendum: Extended scaling and Paschen law for micro-sized radiofrequency plasma breakdown (2017 Plasma Sources Sci. Technol. 26 034003)." Plasma Sources Science and Technology 26, no. 5 (April 5, 2017): 059502. http://dx.doi.org/10.1088/1361-6595/aa6771.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Netzer, Hagai. "Testing broad-line region models with reverberation mapping." Monthly Notices of the Royal Astronomical Society 494, no. 2 (March 19, 2020): 1611–21. http://dx.doi.org/10.1093/mnras/staa767.

Full text

Abstract:

ABSTRACT New reverberation mapping (RM) measurements, combined with accurate luminosities and line ratios, provide strong constraints on the location of the line emitting gas in the broad-line region (BLR) of active galactic nuclei (AGNs). In this paper, I present new calculations of radiation pressure and magnetic pressure confined clouds and apply them to a ‘generic AGN’ and to NGC 5548. The new calculations are in good agreement with the observed lags of all broad emission lines, and with the luminosities of Ly α, C iv 1549, O vi 1035, and He ii 1640. They are also in reasonable agreement with the luminosities of Mg ii 2798 and the 1990 Å blend of C iii] and Si iii] lines for high-metallicity gas. They explain the changes in time-lag following an increase in continuum luminosity and their dependencies on the inner and outer boundaries of the BLR. They also predict very strong Balmer and Paschen continua with important implications to continuum RM experiments. However, the calculated Balmer and Paschen line luminosities are too weak, by factors of 2–5. This ‘Balmer line crisis’ was noted in several earlier works and is now confirmed and constrained by RM measurements that were not available in the past. It seems that present photoionization codes that use the escape probability formalism fail to correctly compute the Balmer line luminosities in high-density, large optical depth gas.

APA, Harvard, Vancouver, ISO, and other styles

36

LING, YI-MING. "Study on breakdown characteristics of a low-pressure dielectric barrier discharge." Journal of Plasma Physics 73, no. 3 (June 2007): 417–26. http://dx.doi.org/10.1017/s0022377806004715.

Full text

Abstract:

AbstractThe breakdown characteristics of a low-frequency dielectric barrier discharge (DBD) at low pressure are investigated experimentally in He, Ne and Ar. The current waveform of this DBD, a series of pulses, is caused by the results of the electron avalanches under the action of the applied field and the quenching effect of the wall-charge field on the avalanches. Taking into consideration the diffusion loss of the charged particles in the breakdown processes, the experimental investigation and the theoretical analysis of its breakdown characteristics indicate that its breakdown voltage is higher than the calculation by the Paschen law and depends on the filled-gas pressure and the distance between the electrodes, instead of their product. The ion-induced secondary electron emission coefficient and the mean electron energy at the moment of breakdown can also be determined approximately by measuring the breakdown characteristics of the discharge tubes with different distances between the electrodes and combining the theoretical deductions. The experimental results and the theoretical analysis of the breakdown characteristics of this DBD are discussed.

APA, Harvard, Vancouver, ISO, and other styles

37

Loveless, Amanda M., and Allen L. Garner. "Erratum: “A universal theory for gas breakdown from microscale to the classical Paschen law” [Phys. Plasmas 24, 113522 (2017)]." Physics of Plasmas 29, no. 9 (September 2022): 099901. http://dx.doi.org/10.1063/5.0121626.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Takeda, Yoichi. "Formation of the Balmer Line in the Optically Thick Nova Envelope." International Astronomical Union Colloquium 122 (1990): 301–2. http://dx.doi.org/10.1017/s0252921100068780.

Full text

Abstract:

Non–LTE effect and formation of the Balmer line Hα in the optically thick nova wind expected from the radiation–pressure–driven continuous ejection model (cf. Bath and Shaviv, 1976; Ruggles and Bath, 1979) was investigated by use of the pure–hydrogen spherical model atmosphere, in which constant radial expansion velocity, inverse square law of density distribution, and planar grey temperature distribution were assumed. The coupled equations of radiative transfer and statistical equilibrium on the four levels plus continuum model atom (in which Hα line and Balmer–, Paschen–, and Brackett– continua are explicitly treated) were solved by the complete linearization procedure based on the comoving frame method (cf. Mihalas and Kunasz, 1978). We calculated four models as results of the combination of the surface density ρsurf (at ᵀRos = 10−13) (10−12 g/cm3, 10−13 g/cm3) and the expansion velocity Vexp (0 km/sec, 1000 km/sec). We assumed 1012 cm for the photospheric radius rph (at ᵀRos = 1), 10000 K for the effective temperature appearing in the temperature formula, and 100 km/sec for the microturbulent parameter. The low density models have larger extension (rsurf/rph ≃4.1) than the high density ones (rsurf/rph ≃1.7).

APA, Harvard, Vancouver, ISO, and other styles

39

Schödel, R., E. Gallego-Cano, H. Dong, F. Nogueras-Lara, A. T. Gallego-Calvente, P. Amaro-Seoane, and H. Baumgardt. "The distribution of stars around the Milky Way’s central black hole." Astronomy & Astrophysics 609 (December 22, 2017): A27. http://dx.doi.org/10.1051/0004-6361/201730452.

Full text

Abstract:

Context. This is the second of three papers that search for the predicted stellar cusp around the Milky Way’s central black hole, Sagittarius A*, with new data and methods. Aims. We aim to infer the distribution of the faintest stellar population currently accessible through observations around Sagittarius A*. Methods. We used adaptive optics assisted high angular resolution images obtained with the NACO instrument at the ESO VLT. Through optimised PSF fitting we removed the light from all detected stars above a given magnitude limit. Subsequently we analysed the remaining, diffuse light density. Systematic uncertainties were constrained by the use of data from different observing epochs and obtained with different filters. We show that it is necessary to correct for the diffuse emission from the mini-spiral, which would otherwise lead to a systematically biased light density profile. We used a Paschen α map obtained with the Hubble Space Telescope for this purpose. Results. The azimuthally averaged diffuse surface light density profile within a projected distance of R ≲ 0.5 pc from Sagittarius A* can be described consistently by a single power law with an exponent of Γ = 0.26 ± 0.02stat ± 0.05sys, similar to what has been found for the surface number density of faint stars in Paper I. Conclusions. The analysed diffuse light arises from sub-giant and main-sequence stars with Ks ≈ 19−22 with masses of 0.8−1.5 M⊙. These stars can be old enough to be dynamically relaxed. The observed power-law profile and its slope are consistent with the existence of a relaxed stellar cusp around the Milky Way’s central black hole. We find that a Nuker law provides an adequate description of the nuclear cluster’s intrinsic shape (assuming spherical symmetry). The 3D power-law slope near Sgr A* is γ = 1.13 ± 0.03model ± 0.05sys. The stellar density decreases more steeply beyond a break radius of about 3 pc, which corresponds roughly to the radius of influence of the massive black hole. At a distance of 0.01 pc from the black hole, we estimate a stellar mass density of 2.6 ± 0.3 × 107 M⊙ pc-3 and a total enclosed stellar mass of 180 ± 30 M⊙. These estimates assume a constant mass-to-light ratio and do not take stellar remnants into account. The fact that a flat projected surface density is observed for old giants at projected distances R ≲ 0.3 pc implies that some mechanism may have altered their appearance or distribution.

APA, Harvard, Vancouver, ISO, and other styles

40

Molina, Juan, Edo Ibar, Nicolás Godoy, Andrés Escala, Tomonari Michiyama, Cheng Cheng, Thomas M. Hughes, et al. "VALES." Astronomy & Astrophysics 643 (November 2020): A78. http://dx.doi.org/10.1051/0004-6361/202039008.

Full text

Abstract:

Context. Spatially resolved observations of the ionized and molecular gas are critical for understanding the physical processes that govern the interstellar medium (ISM) in galaxies. The observation of starburst systems is also important as they present extreme gas conditions that may help to test different ISM models. However, matched resolution imaging at ∼kpc scales for both ISM gas phases are usually scarce, and the ISM properties of starbursts still remain poorly understood. Aims. We aim to study the morpho-kinematic properties of the ionized and molecular gas in three dusty starburst galaxies at z = 0.12−0.17 to explore the relation between molecular ISM gas phase dynamics and the star-formation activity. Methods. We employ two-dimensional dynamical modelling to analyse Atacama Large Millimeter/submillimiter Array CO(1–0) and seeing-limited Spectrograph for INtegral Field Observations in the Near Infrared Paschen-α (Paα) observations, tracing the molecular and ionized gas morpho-kinematics at ∼kpc-scales. We use a dynamical mass model, which accounts for beam-smearing effects, to constrain the CO-to-H2 conversion factor and estimate the molecular gas mass content. Results. One starburst galaxy shows irregular morphology, which may indicate a major merger, while the other two systems show disc-like morpho-kinematics. The two disc-like starbursts show molecular gas velocity dispersion values comparable with those seen in local luminous and ultra luminous infrared galaxies but in an ISM with molecular gas fraction and surface density values in the range of the estimates reported for local star-forming galaxies. We find that these molecular gas velocity dispersion values can be explained by assuming vertical pressure equilibrium. We also find that the star-formation activity, traced by the Paα emission line, is well correlated with the molecular gas content, suggesting an enhanced star-formation efficiency and depletion times of the order of ∼0.1−1 Gyr. We find that the star-formation rate surface density (ΣSFR) correlates with the ISM pressure set by self-gravity (Pgrav) following a power law with an exponent close to 0.8. Conclusions. In dusty disc-like starburst galaxies, our data support the scenario in which the molecular gas velocity dispersion values are driven by the ISM pressure set by self-gravity and are responsible for maintaining the vertical pressure balance. The correlation between ΣSFR and Pgrav suggests that, in these dusty starbursts galaxies, the star-formation activity arises as a consequence of the ISM pressure balance.

APA, Harvard, Vancouver, ISO, and other styles

41

Palomares, J. C., Pedro Guillermo Reyes, A. Gómez, M. J. Rodríguez, C. Torres, J. Vergara, and H. Martínez. "Experimental study of the modified Paschen's law: glow discharge of Ethanol (CH3CH2OH), Methanol (CH3OH) and its mixture." Revista Mexicana de Física 68, no. 4 Jul-Aug (June 23, 2022). http://dx.doi.org/10.31349/revmexfis.68.041502.

Full text

Abstract:

A low-pressure ethanol and methanol discharge produced by a DC electric field was studied experimentally, analyzing the disruptive voltage between parallel electrodes with a circular geometry as function of pressure and distance according with the Paschen’s law, this states that the breakdown voltage is a function of the product of gas pressure and distance following the relationship: VB = f(pd). Detailed knowledge of the minimum breakdown voltage required to initiate the ethanol–methanol discharge will be useful to providing important information for future experiments and applications. In this experiment, a cylindrical chamber was used to generate a glow discharge of the ethanol (CH3CH2OH), methanol (CH3OH), and 50% mixture, over a pressure range of 0.07–5.00 Torr. Optical emission spectroscopy was performed in the wavelength range of 200–900 nm. The Paschen curves, measured experimentally for ethanol and methanol are presented, taking in account the coefficient obtained using the variation in Paschen’s law as a function of the distance and radius of the electrodes (d/r).

APA, Harvard, Vancouver, ISO, and other styles

42

Shi, Zhipeng, Yongqiang Kang, Jialin Zhang, Shuaibing Li, and Hongwei Li. "A Novel Theoretical Model of Gas-Solid Two-Phase Flow Mixed Dielectric Discharge." Physics of Fluids, October 12, 2022. http://dx.doi.org/10.1063/5.0124376.

Full text

Abstract:

A theoretical physical model of gas-solid two-phase flow mixed dielectric discharge in a uniform field based on Townsend's discharge theory is presented. This model extends the classical Townsend's theory to be applicable to the quantitative analysis of dielectric discharge questions related to gas-solid two-phase flow environment, reveals the influence mechanism of flowing gases and solid-phase particles on discharge, and provides a theoretical basis for expanding the application of discharge plasma technology in various fields. In the model, based on the basic physical process of gas discharge and our previous articles, the effects of the attraction and obstructive factors of solid-phase particles on the number density of electrons or ions and the local space electric field in the inception and development of gas discharge were taken into account. On this basis, the analytical expression of breakdown voltage in gas-solid two-phase flow mixed dielectric is obtained, the Paschen's law of gas breakdown is modified, and the Townsend's breakdown criterion of gas-solid two-phase flow environment is proposed. It is shown that the breakdown voltage of gas-solid two-phase flow mixed dielectric decreases with increasing gas flow velocity. The gas flow velocity is the main factor affecting the variation trend of the breakdown voltage. The concentration and size of solid-phase particles determine the values of breakdown voltage. The breakdown voltage of smaller size and higher concentration of solid-phase particles is greater, which has a stronger suppression effect on the discharge.

APA, Harvard, Vancouver, ISO, and other styles

43

Loveless, Amanda M., Guodong Meng, Qi Ying, Feihong Wu, Kejing Wang, Yonghong Cheng, and Allen L. Garner. "The Transition to Paschen’s Law for Microscale Gas Breakdown at Subatmospheric Pressure." Scientific Reports 9, no. 1 (April 5, 2019). http://dx.doi.org/10.1038/s41598-019-42111-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Xia, Xin, Jingjing Fu, and Yunlong Zi. "A universal standardized method for output capability assessment of nanogenerators." Nature Communications 10, no. 1 (September 27, 2019). http://dx.doi.org/10.1038/s41467-019-12465-2.

Full text

Abstract:

Abstract To quantitatively evaluate the output performance of triboelectric nanogenerators, figures of merit have been developed. However, the current figures of merit, without considering the breakdown effect that seriously affects the effective maximized energy output, are limited for application. Meanwhile, a method to evaluate output capability of nanogenerators is needed. Here, a standardized method that considers the breakdown effect is proposed for output capability assessment of nanogenerators. Contact separation and contact freestanding-triboelectric-layer modes triboelectric nanogenerators are used to demonstrate this method, and the effective maximized energy output and revised figures of merit are calculated based on the experimental results. These results are consistent with those theoretically calculated based on Paschen’s law. This method is also conducted to evaluate a film-based piezoelectric nanogenerator, demonstrating its universal applicability for nanogenerators. This study proposes a standardized method for evaluating the effective output capability of nanogenerators, which is crucial for standardized evaluation and application of nanogenerator technologies.

APA, Harvard, Vancouver, ISO, and other styles

45

Kartalović, Nenad, Alija Jusić, Dušan Nikezić, and Koviljka Stanković. "Validity of the law of similarity for impulse and DC breakdown of gases in the vicinity of the Paschen’s minimum." Vacuum, November 2022, 111683. http://dx.doi.org/10.1016/j.vacuum.2022.111683.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

J, Ananthanarasimhan, and Lakshminarayana Rao. "Effect of gas flow rate on breakdown voltage in a rotating gliding arc reactor." Frontiers in Advanced Materials Research, May 26, 2021, 42–46. http://dx.doi.org/10.34256/famr2115.

Full text

Abstract:

Understanding breakdown phenomena in rotating gliding arc discharge (RGA) is of interest to tailor them for specific applications. This work revealed that the breakdown voltage in a RGA reactor was not dictated by collisional effects i.e., change in flow rate. The observation was consistent for both the discharge gas medium argon and nitrogen. The collisional effect variation was implemented by varying the operating flow rates i.e., 5 SLPM which is transitional in nature, and 50 SLPM which is turbulent in nature having localized micro-eddies. The observation also indicated failure of Paschen law in RGA having shortest gap between the electrodes of order of mm, operated under atmospheric pressure conditions. Collisional ineffectiveness indicates possibility of streamer formation which needs to be further investigated in future. This work marks preliminary and important step towards understanding the breakdown phenomena in atmospheric RGAs operated under different flow regimes such as laminar/transitional and turbulent.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!