Phenomenological model of the unstable stage of a vacuum spark discharge

Barengolts, S. A.; Mesyats, G. A.; Perelstein, E. A.

doi:10.1134/s1063784209100077

Cited by 8 publications

(10 citation statements)

References 5 publications

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“…Among the ion acceleration mechanisms considered in [1][2][3][4][5][16][17][18], a well-working scheme with a virtual cathode is notable [6][7][8][9][10]. The plasma E×B discharges, on the other hand, showed positive potential jumps with Δj<V d [36][37][38][39]45].…”

Section: Discussionmentioning

confidence: 99%

“…The model of anomalous ion acceleration based on the concept of a nonstationary potential well was developed consistently in [8][9][10]. It was shown that in the unstable mode of a vacuum discharge the electron emission current exceeds the Child-Langmuir limit, which is accompanied by the generation of a virtual cathode with amplitude of up to 80% of V d [8].…”

Section: Introductionmentioning

confidence: 99%

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Anomalous acceleration of ions in a plasma accelerator with an anodic layer

Bardakov

Ivanov

Kazantsev

et al. 2018

Plasma Sci. Technol.

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In a plasma accelerator with an anodic layer (PAAL), we discovered experimentally the effect of 'super-acceleration' of the bulk of the ions to energies W exceeding the energy equivalent to the discharge voltage V d. The E×B discharge was ignited in an environment of atomic argon and helium and molecular nitrogen. Singly charged argon ions were accelerated most effectively in the case of the largest discharge currents and pressure P of the working gas. Helium ions with W>eV d (e being the electron charge) were only recorded at maximum pressures. Molecular nitrogen was not accelerated to energies W>eV d. Anomalous acceleration is realized in the range of radial magnetic fields on the anode 2.8×10-2 B rA 4×10-2 T. It was also found analytically that the cathode of the accelerator can receive anomalously accelerated ions. In this case, the value of the potential in the anodic layer becomes higher than the anode potential, and the anode current exceeds some critical value. Numerical modeling in terms of the developed theory showed qualitative agreement between modeling data and measurements.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Anomalous acceleration of ions in a plasma accelerator with an anodic layer

Bardakov

Ivanov

Kazantsev

et al. 2018

Plasma Sci. Technol.

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“…But the dense plasma size is about 100 ps • 10 9 cm/s = 0.1 cm, what is much less than Coulomb collision length (for 10 keV, 10 19 cm −3 λ Col ∼ 10 12 T 2 /n ∼ 10 cm). Therefore neither collisional dissipating of the beamenergy nor the static redistribution of potential is not sufficient to provide the beam termination and we have to consider collisionless mechanisms [13][14][15][16][17][18][19][20][21].…”

Section: Discharge Parametersmentioning

confidence: 99%

“…The virtual cathode oscillations have a period ∼ 1/ω pe [18], where ω pe is the plasma Langmuir frequency: ω pe = (4πn pl e 2 /m e ) 0.5 ≈ 0.57 • 10 5 • (n pl, cm −3 ) 0.5 [s −1 ], where n pl is equal to the beam density. The last one can be estimated as 10 11 cm −3 -10 12 cm −3 .…”

Section: Collective Electrostatic Processesmentioning

confidence: 99%

Electrostatic-Instabilities as a Source of Picosecond Termination of Runaway-Electrons Beam in High-Voltage Gas-Filled Ultra-Fast Diode

Tsventoukh¹,

Mesyats²,

Sergey

2010

Plasma and Fusion Research

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The fast disruption of the runaway electrons-beam in a high-voltage picosecond atmospheric-discharge [G. A. Mesyats and M. I. Yalandin, IEEE Trans. Plas. Sci. 37 785 ( 2009)] is considered. The plasma electrostatic instabilities are proposed as a mechanism of such disruption. Strong over-voltage (more than 1 MV/cm at gas pressure 1 atm) provides an intense electrons-acceleration in the runaway regime. It is shown that neither collisions nor a static potential profile could deliberately prevent this runaway regime. Whereas, the cathodeanode bridging impossible within tens of pisoseconds. It is obtained that the characteristic times of a simplest electrostatic-instabilities build-up are consistent with the observed runaway-electrons beam-duration at the certain plasma density, which was considered as a parameter. The agreement our estimation results and the measurements [G. A.

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“…1 Nonstationary diode may be characterized by current density more than Child-Langmuir current. 2,3 For electron bunch possibility of such current increasing was shown in papers, 4 where the dependence of anode current on electron thermal velocity and bunch longitudinal emittance was found. In case of ion diode boundary conditions for particle extraction are differed from those in case of electron diode, because extraction surface or plasma meniscus is rather movable, and one should take into account ion preacceleration in Langmuir sheath, or, more accurately, in presheath and sheath.…”

Section: Introductionmentioning

confidence: 96%