Runaway electrons and current density in the cathode region of a vacuum arc

Djakov, B. E.

doi:10.1088/0022-3727/22/2/023

Cited by 6 publications

(2 citation statements)

References 6 publications

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“…Additionally to electrons with relatively low energy (Maxwell distribution with 1-2 eV), high-energy electrons (runaway electrons) were predicted theoretically (Djakov 1989) and observed experimentally (Ivanov er al 1990). From the data given in the latter paper the energy carried by runaway electrons can be estimated to be E: = N:E: Depending on what is chosen from the literature as a 'true' value, the sum of all contributions to the energy balance varies by approximately 10%.…”

Section: How Is the Energy Input Distributed And How Large Is The Rad...mentioning

confidence: 94%

Emission spectroscopy of low-current vacuum arcs

Anders¹,

Anders²

1991

J. Phys. D: Appl. Phys.

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Spectra of copper vapour arcs in a vacuum (20 A-1 kA) are compared with the previously reported spectrum of a copper vapour spark in vacuum. In contrast to the latter, the spectra of the arcs consist mainly of Cu I and Cu II lines but only of a few lines of Cu III. The energy balance of a vacuum arc is discussed in a simplified manner taking a 100 A copper arc as an example. The results are: (i) the input energy is mainly transferred into heating of the cathode, kinetic energy of ions, enthalpy of electrons, ionization energy of ions, and energy invested in electron emission (latent work function). All other contributions are negligibly small. (ii) The electron temperature relatively far away from the spot centre (>100 mu m) can hardly exceed 2 eV. (iii) Since the number of photons emitted by the arc spot plasma is relatively small, it is not possible to perform plasma diagnostics by emission spectroscopy with simultaneous spectral, spatial and temporal resolution.

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Section: How Is the Energy Input Distributed And How Large Is The Rad...mentioning

confidence: 94%

Emission spectroscopy of low-current vacuum arcs

Anders¹,

Anders²

1991

J. Phys. D: Appl. Phys.

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“…В случае низкого давления даже такая небольшая энергия может быть достаточна для перехода электронов из высокоэнергетической части функции распределения по энергии в режим убегания. Такое явление также широко известно и неоднократно упоминалось в литературе (см., например, [12,13]). С увеличением давления возможность генерации убегающих электронов в катодном слое становится менее вероятной.…”

Section: Introductionunclassified

Численное Исследование Возможности Генерации Убегающих Электронов В Формирующемся Катодном Слое Самостоятельного Объемного Разряда Высокого Давления

Лисенков¹

2020

Журнал Технической Физики

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Calculations of the formation of the cathode layer of an self-sustained high-pressure volume discharge with pre-ionization of the gas medium excited by nano-and subnanosecond voltage pulses are carried out. It is shown that at pressures of ~ 1 atm at the final stage of the cathode layer formation, conditions for the generation of escaping electrons arise. We also considered the transition of electrons into runaway mode from the area of electric field amplification in front of the plasma (streamer) channel, which originates from the top of the micro-spike on the cathode. It is shown that at pressures of ~ 10 atm, electrons can transfer into runaway mode immediately after emission from the top of micro-spike in amplified electric field. Thus obtained runaway electrons can create pre-ionization of the gaseous medium and provide the formation of the initial phase of the discharge in volume form in the system without external pre-ionization.

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On current filament formation in arc cathode plasmas

Serapinas

Kupliauskiene

1994

J. Phys. D: Appl. Phys.

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Electron current stability in relation to filament formation in aluminum plasma at densities from 1 to 1000 atm (105-108 pa) has been studied. Electron momentum relaxation times obtained, including Coulomb and inelastic collisions, were in the picosecond and smaller time scale, and increase in the temperature interval 104-2*104 K. This results in similar electron conductivity temperature dependence. Electron energy losses due to ionization and excitation of atomic particles in the temperature range mentioned above are almost constant. At such conditions electron temperature fluctuations in the plasma must increase, leading to electron current filamentation. The line radiation can work as a stabilizing factor, but it becomes effective only in the nanosecond time scale or at low plasma densities. The process seems to be of importance in relation to the current fragmentation at the arc cathode spot.

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Runaway electrons and current density in the cathode region of a vacuum arc

Cited by 6 publications

References 6 publications

Emission spectroscopy of low-current vacuum arcs

Emission spectroscopy of low-current vacuum arcs

Численное Исследование Возможности Генерации Убегающих Электронов В Формирующемся Катодном Слое Самостоятельного Объемного Разряда Высокого Давления

On current filament formation in arc cathode plasmas

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