Time-dependent plasma, electron kinetics

According to the relevant power and momentum balance, Eqs. (38) and (39), the electron kinetics in steady-state plasmas is characterized by tbe conditions that at any instant the power and the momentum input from the electric field are dissipated by elastic and inelastic electron collisions into the translational and internal energy of the gas particles. This instantaneous complete compensation of the respective gain from the field and the loss in collisions usually does not occur in time-dependent plasmas, and often the collisional dissipation follows with a more or less large delay—for example, the temporally varying action of a time-dependent field. Thus, the temporal response of the electrons to certain disturbances in the initial value of their velocity distribution or to rapid changes of the electric field becomes more complicated, and the study of kinetic problems related to time-dependent plasmas naturally becomes more complex and sophisticated. Despite this extended interplay between the action of the binary electron collisions and the action of the electric field, the electron kinetics in time-... 

Furthermore, the detailed procedure ultimately used to determine the velocity distribution sensitively depends on the type of plasma and is quite different when studying the electron kinetics in steady-state, time-dependent, or space-dependent plasmas. 

Equations (12), simplified by the assumption of isotropic scattering in exciting and dissociating collisions, represent the basic equations for studying many quite different problems in electron kinetics. In particular, the additional simplification to steady-state, purely time-dependent, or purely space-dependent plasma conditions allows a detailed microphysical analysis of various electron kinetic problems related to each of these plasma conditions. 

In these time-dependent kinetic studies, a variety of electron collision processes similar to those treated in the steady-state kinetics has been treated. In addition to these processes, nonconservative electron collision processes, such as ionization and attachment, and even the nonlinear electron-electron interaction have been taken into accoimt. Besides the various types of electron collisions, other electron generation and destruction processes, such as the chemo-ionization in collisions between excited heavy particles in decaying plasmas or the injection of beamlike electrons into plasma, have been included as particle sources or sinks... 

By the preceding representations, an attempt has been made to give, on the basis of the electron Boltzmann equation, an introduction to the kinetic treatment of the electron component in steady-state, time-dependent, and space-dependent plasmas and to illustrate by selected examples the large variety of electron kinetics in anisothermal weakly ionized plasmas. 

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