Interaction processes with creation of fast electrons in the low temperature plasma

Abstract

The methods and the results of investigations of the reactions in which electrons appear with energies surpassing the average electron distribution's energy in a plasma are considered. Particular attention is paid to the plasma electron spectroscopy method, which combines the advantages of the elementary processes examination in a plasma with the possibilities of conventional electron spectroscopy. Data of the study of chemiionization reactions involving two excited rare gas atoms, Penning ionizations of atoms and molecules by the helium metastable atoms and quenching of excited inert gases and mercury atoms by the electrons are given. The influence of the processes of creating fast electrons on the plasma properties is discussed.

Semianalytical description of nonlocal secondary electrons in a radio frequency capacitively coupled plasma at intermediate pressures

“…Inclusion of ionization of metastable atoms into the model is rather cumbersome, since it requires recalculation of the Townsend coefficient. The electron excitation and ionization of metastables influence EDF [11], so that a correct model for the Townsend coefficient should include dependence on the metastable atom density as well. The contribution of the metastable atoms to the ionization is negligible at higher current densities [12].…”

“…So secondary electrons are not capable of further ionization and can be excluded from consideration. Thus, the kinetic equation for the electrons in light gases (H, He) reads (11) Equation (11) can be easily integrated along characteristics…”

Collisional electron spectroscopy method for gas analysis

“…If the energy of penning electrons is p > w (where w is the potential between axis and discharge wall), these electrons reach the wall in a free diffusion. In the absence of electric field or when it has a small value (e.g., negative glow plasma, beam plasma), where T e , and hence e w are small, the energy spectrum of penning electrons represent sharp peaks near energies p , reproducing the spectrum R ) of reactions of type (1) [1][2][3]. Using the measured penning electrons spectra R( ) and the well known rate constants for Penning reactions one can identify the impurities and determine their concentrations.…”

“…[1] represents a new approach for studies of elementary plasma processes and atomic constants. On the base of the PLES method a new method for identification of gas impurities is proposed by Kudryavtsev [2].…”

“…Further development of PLES method for identification of unknown species in a gas phase is reported in [3]. In [1][2][3] the nonlocal afterglow plasma of positive column at low pressures (0.5 -3.5 Torr) is used, and temporal resolution of the registration system is applied, which complicates the devices.…”