Energy balance in low-pressure gas discharges

Abstract

In the positive column of low-pressure gas discharges, the electron energy distribution can be markedly non-Maxwellian, in particular in the tail of the distribution at low degrees of ionization. A method is described which enables one to account for large deviations from a Maxwellian distribution when calculating collision rates, energy flow terms, excited-state densities, and the radiation output. Illustrative examples are given for Cs–Ar, Ar, and Hg–Ar discharges. Possible extensions and applications of the method are briefly discussed. Analytical formulas are derived for (i) the Coulomb relaxation between the electrons and (ii) the cross sections for ionization from excited states.

A staggered-mesh finite-difference numerical method for solving the transport equations in low pressure rf glow discharges

“…In accordance with Ref. [21], a three-level model consisting of a ground state, an excited state with E, = 11.60 eV (representing the first four excited states Pz, Pi, Pi, and Pi with threshold energies 11.55, 11.62, 11.74, and 11.83 eV, respectively), and an ion ground state with e2 = 15.76 eV. The total cross section data as a function energy has been obtained from standard sour-ces [ 22,231.…”

“…Future work by the authors involving rf glow discharge modeling will include a thorough comparison of this model with a quasistatic "drift-diffusion" model [S] to investigate nonequilibrium electron effects and the development of experiments to further examine the model's validity. Moreover, the potential for utilizing a multi-group electron model [21] to include electronelectron and superelastic collisions will be investigated.…”

Computational Study of Resonantly Ionizing Rubidium Vapor by Nanosecond Laser Pulses

“… is the spectral irradiance of the radiation field at frequency  appropriate to the 2  1 transition, B 21 represents Milne coefficient, and 21 ) represents the irradiative recombination rate coefficient to level n [19].  is the two photon, resonance state ionization rate coefficient and F represents the photon flux density.…”

Effect of radiation and non-maxwellian electron distribution on relaxation processes in an atmospheric cesium seeded argon plasma

“…The model includes radiative transitions and the possibility of a deviation from the Maxwellian electron energy distribution. The two electron group model is used to describe the electron distribution (3,4). The different contributions of the electrons belonging to the two groups to the non-elastic collisions are then considered.…”