Transient phenomena during dense argon micro-plasma formation

Abstract

We report on transient generation of highly ionized (ionization degree ~10%) argon microplasma using a self-consistent fluid plasma model coupled with the compressible Navier-Stokes equations. The plasma is generated within a micrometer size cathode spot immediately after the onset of intense secondary electron emission from the cathode and exists over a relatively short duration of ~10 ns. We observe the electron pressure within this microplasma exceeding the background gas pressure by a few times and discuss the mechanisms of the energy transfer from this plasma to the heavy species. The localized gas heating generates a compression wave that propagates from the cathode to the anode.

Investigation on transient process of dense hydrogen microdischarge by dual-wavelength laser interferometry

“…n n is the density of the heavy particle, v th is the electron thermal velocity, and σ m is the momentum transport cross section. Assuming that the electron temperature is 1 eV [1], v th = √ 3kBTe me is approximately 7 × 10 5 ms −1 . The density of the heavy particle can be set as 3 × 10 23 m −3 according to the gas pressure.…”

“…Microdischarge is characterized by small discharge dimensions, usually hundreds of microns to millimeters, at high gas pressures, which has gained a great deal of interest over the past decade due to its wide application [1][2][3][4][5]. Although the total power itself is very small, the corresponding power density in microdischarging is several orders of magnitude higher than that of classical glow discharge.…”

“…The high-power * Authors to whom any correspondence should be addressed. density is accompanied by extremely high electron density, ranging from 10 18 m −3 to 10 20 m −3 [1]. Simulations of kinetic processes in microdischarges suggest substantial changes of the electron temperature and the electron density on a nano-or subnanosecond time scale [1,6].…”

“…density is accompanied by extremely high electron density, ranging from 10 18 m −3 to 10 20 m −3 [1]. Simulations of kinetic processes in microdischarges suggest substantial changes of the electron temperature and the electron density on a nano-or subnanosecond time scale [1,6]. Because of transient variations in these dense plasmas, the discharges are often described by different modes, such as plasma filament [7], streamer [8] and spark [9] depending on the experimentally observed plasma shapes.…”

“…In simulation, Donkó et al studied the dynamics of a nanosecond pulsed hydrogen microdischarge at nearly atmospheric pressure, and showed the time resolved current, electric field, electron density, and spatio-temporal excitation rates [10]. More recently, Levko et al reported on the detailed breakdown dynamics and transient phenomena of microplasma by a single-pulse discharge in the simulation [1,6,11]. The discharge is described as three distinctive stages: (a) the build-up of the space charge in the vicinity of the anode, (b) the movement of the ionization wave from the anode to the cathode, and formation of the cathode spot characterized by highly ionized plasma, and (c) the plasma relaxation.…”