ABSTRACT
Inhomogeneities in Currentless Multispecies Plasmas with Great Distinction in Partial Temperatures In numerous applications extremely nonisotermal plasmas arise. In gas discharges at low and moderate pressures, for example, the characteristic values of T/Tt is of the order of 102. We shall demonstrate in this Chapter that this factor, in analogy with a dc current, in multispecies inhomogeneous plasmas can result in the propagation of weakly damping perturbations: signals. Since in the majority of practically important discharges rather complex gas mixtures are used, the situation when several ion species are present in the plasma is typical. Very important case corresponds to the discharges in the electronegative gases. They are widely used in the technology and surface processing. It is to be noted that the ordinary air is also considerably electronegative. Therefore, the concept of overturn of smooth plasma density profiles, formation of strongly inhomogeneous shock-like plasma structures and the flux conservation in these shocks turns out to be also very effective in this important case of currentless strongly nonisothemal plasmas. As an example, we shall chose the gas discharge plasmas with Te» T j. In the first Section of this Chapter we shall consider the dynamical problem in the absence of plasmachemical reactions. The stationary positive column of a dc discharge in an electronegative gas is studied in the second Section. The third Section treats the capacitively coupled RF discharges in electronegative gases. In order to simplify the mathematics, we shall restrict ourselves to the plasmas with only two species of ions, both positive, or one positive and one negative.
