Mechanism and dynamics of picosecond radial breakdown of a gas-filled coaxial line

Abstract

High-voltage picosecond breakdown of an atmospheric-pressure air-filled coaxial line in the radial electric field of a propagating transverse electromagnetic wave has been studied both experimentally and theoretically. On the one hand, we demonstrate that gas preionization by runaway electrons (RAEs) plays a decisive role in the breakdown development process: the breakdown delay time drastically increases in the absence of RAEs. On the other hand, it is established that, for sufficiently short pulses, the radial gap switching process does not have enough time to develop even in a situation where the RAE flow is effectively generated. Fundamental limitations on the breakdown strength of gas coaxial feeders imposed by this effect are discussed.

Emission Features and Structure of an Electron Beam versus Gas Pressure and Magnetic Field in a Cold-Cathode Coaxial Diode

“…Judging by the reflectograms, in the latter case, distributed breakdowns occurred in the CTL when a supply pulse was delivered to the cathode. For this, for example, at p = 760 Torr, amplitudes U c exceeding (modulo) 155 kV with the pulse duration of >270 ps were sufficient, which was demonstrated earlier [65,80].…”

Длительность Пучка Убегающих Электронов При Субнаносекундном Фронте Импульса Напряжения

“…Большое внимание уделяется изучению параметров пучков УЭ в лабораторных разрядах при повышенных давлениях воздуха и других газов, а также рентгеновского излучения под воздействием пучка убегающих электронов (ПУЭ) [8][9][10][11][12][13][14][15][16][17][18][19]. Значительная часть этих исследований проводится в условиях пробоя сантиметровых промежутков с катодами малого радиуса кривизны, заполненных воздухом при атмосферном давлении.…”

“…Изучаются как параметры тока ПУЭ в различных условиях, так и механизм генерации УЭ. Исследования также проводятся посредством моделирования разрядов с УЭ, см., например, [9][10][11]15,[20][21][22].…”

Duration of runaway electron current pulses when applying voltage pulses with a subnanosecond rise time

“…Much attention is paid to the study of the parameters of RE beams in laboratory discharges at high pressures of air and other gases, as well as X-ray radiation under the influence of a RE beam (REB) [8][9][10][11][12][13][14][15][16][17][18][19]. A significant part of these studies is carried out under conditions of breakdown of centimeter-sized gaps with abrupt cathodes filled with air at atmospheric pressure.…”

“…Both the current parameters of the REB under various conditions and the mechanism of generation of RE are studied. Studies are also carried out by modeling discharges with RE, see, for example, [9][10][11]15,[20][21][22].…”