scholarly journals Electric Breakdown in Long Discharge Tubes at Low Pressure (Review)

2020 ◽  
Vol 46 (10) ◽  
pp. 1015-1044 ◽  
Author(s):  
Yu. Z. Ionikh
Keyword(s):  
Electric Field ◽  
High Speed ◽  
External Circuit ◽  
Electrical Characteristics ◽  
Visible Radiation ◽  
Discharge Tubes ◽  
External Sources ◽  
Ionization Waves ◽  
Low Pressures ◽  
Discharge Gap

Abstract The review is devoted to studies of the processes and mechanisms of ignition of a glow discharge in tubes whose length significantly exceeds their diameter (long discharge tubes) at low pressures (~10 Torr and lower) and moderate voltage rise rates (~1 kV/μs and lower). The electric field in such tubes before a breakdown is substantially nonuniform. Therefore, a breakdown occurs after an ionization wave (or waves) passes through the discharge gap at a speed of ~105–107 cm/s. This makes the characteristics of the breakdown in long tubes significantly different from the breakdown between large and closely spaced electrodes, where the electric field is uniform before the breakdown and where the Townsend or, under strong overvoltage, streamer mechanism is realized. On the other hand, the nature of these processes is very different from those occurring in nanosecond discharges, which arise at voltages with a steepness of ~1 kV/ns and higher and are associated with high-speed (~109 cm/s) ionization waves. The review is based on the materials of experimental and computational works published from 1938 to 2020. Breakdown processes, optical and electrical characteristics of the discharge gap during breakdown, and the influence of the external circuit parameters and external actions (shielding and illumination by external sources of visible radiation) are analyzed.

scholarly journals Ionization Waves Enhance the Production of X-rays during Streamer Collisions

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1101
Author(s):  
Vernon Cooray ◽  
Gerald Cooray ◽  
Marcos Rubinstein ◽  
Farhad Rachidi
Keyword(s):  
Experimental Data ◽  
Electric Field ◽  
Electric Fields ◽  
Time Synchronization ◽  
Field Enhancement ◽  
Opposite Polarity ◽  
X Rays ◽  
Weakly Conducting ◽  
Ionization Waves ◽  
Discharge Gap

Experimental data show that in laboratory sparks, X-rays are produced in time synchronization with the meeting of streamers of opposite polarity just before the final breakdown of the discharge gap. It has been suggested that the electric field enhancement created during the collision of streamers could provide the necessary conditions for electron acceleration, even though some of the theoretical studies show that the duration of the electric field is not long enough to do so. The experimental data on laboratory discharges show that. when streamers of opposite polarity meet each other, a potential or ionization wave that renders the streamer channels conducting is initiated. This paper shows that these ionization waves that convert the discharge channels from weakly conducting to highly conducting are associated with electric fields large enough to accelerate electrons to relativistic energies.

scholarly journals Effect of Graphene Doping Level near the Metal Contact Region on Electrical and Photoresponse Characteristics of Graphene Photodetector

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4661
Author(s):  
Jaedong Jung ◽  
Honghwi Park ◽  
Heungsup Won ◽  
Muhan Choi ◽  
Chang-Ju Lee ◽  
...  
Keyword(s):  
Electric Field ◽  
Doping Level ◽  
High Speed ◽  
High Performance ◽  
Contact Region ◽  
Metal Contact ◽  
Electrical Characteristics ◽  
Short Channel ◽  
Level Difference ◽  
Graphene Doping

Graphene-metal contact is crucial to fabricate high-performance graphene photodetectors since the external quantum efficiency (EQE) of the photodetector depends on the contact properties, and the influence of the contact properties is particularly dominant in short channel devices for high-speed applications. Moreover, junction properties between the channel graphene and graphene near the contact are also important to analyze the photoresponse because the built-in electric field in the junction determines the EQE of the photodetector. In this study, we investigated a relation between the photoresponse and the built-in electric field induced from the doping level difference in the junction between the channel graphene and graphene near the contact. The photoresponse could be enhanced with a high junction barrier height that is tuned by the doping level difference. In addition, we observed that the improved electrical characteristics of channel graphene do not guarantee the enhancement of the photoresponse characteristics of graphene photodetectors.

Design of High-Speed Multilayer IPMSM Using Ferrite PM for EV Traction Considering Mechanical and Electrical Characteristics

2021 ◽  
Vol 57 (1) ◽  
pp. 327-339
Author(s):  
Young-Hoon Jung ◽  
Min-Ro Park ◽  
Ki-O Kim ◽  
Jun-Woo Chin ◽  
Jung-Pyo Hong ◽  
...  
Keyword(s):  
High Speed ◽  
Electrical Characteristics

On minimum of static breakdown voltage for gas-filled gap

2021 ◽  
pp. 59-64
Author(s):  
A.V. Kozyrev ◽  
◽  
V.Yu. Kozhevnikov ◽  
A.O. Kokovin ◽  
S.Y. Medvedev ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Electric Field ◽  
Breakdown Voltage ◽  
Spherical Geometry ◽  
The Self ◽  
Planar Geometry ◽  
Plane Parallel ◽  
Discharge Gap

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.

scholarly journals Dielectrophoretic classification of fibres: principles and application to glass fibres suspended in air

2019 ◽  
Vol 213 ◽  
pp. 02053
Author(s):  
Frantisek Lizal ◽  
Milan Maly ◽  
Jakub Elcner ◽  
Arpad Farkas ◽  
Ondrej Pech ◽  
...  
Keyword(s):  
Electric Field ◽  
High Speed ◽  
Deposition Velocity ◽  
Uniform Electric Field ◽  
Electrical Mobility ◽  
Mobility Separation ◽  
Neutral Particles ◽  
Naturally Occurring ◽  
Two Parameters

Particles exposed to an electric field experience forces that influence their movement. This effect can be used for filtration of air, or for size classification of aerosols. The motion of charged particles in a non-uniform electric field is called electrophoresis. Two processes are involved in this phenomenon: 1) charging of particles and 2) electrical mobility separation. If fibres are exposed to electrophoresis, they are separated on the basis of two parameters: diameter and length. Regrettably, as naturally occurring fibres are polydisperse both in diameter and length, the electrophoresis is not very efficient in length classification. In contrast, dielectrophoresis is the motion of electrically neutral particles in a non-uniform electric field due to the induced charge separation within the particles. As deposition velocity of fibres induced by dielectrophoretic force strongly depends on length and only weakly on diameter, it can be used for efficient length classification. Principles of length classification of conducting and non-conducting fibres are presented together with design of a fibre classifier. Lastly, images of motion of fibres recorded by high-speed camera are depicted.

scholarly journals Collision of ionization waves in long discharge tubes

2019 ◽  
Vol 1 (2) ◽  
pp. 025004 ◽  
Author(s):  
A I Shishpanov ◽  
D O Ivanov ◽  
S A Kalinin
Keyword(s):  
Discharge Tubes ◽  
Ionization Waves
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