The conceptual development of stationary plasma thrusters

The history of the development of the concept of the stationary plasma thruster is described. The data obtained indicate the possibility of creating extended (over a distance substantially longer than the Debye radius) electric fields in a fully ionized plasma with a relatively high electron temperature (T_e>10 eV) and a conductivity close to the classical one. Based on these results, a number of fundamentally new plasma-dynamic systems were proposed; in particular, the principles of plasma optics were formulated and verified experimentally. In the course of these investigations, new physical processes, such as the formation of the distribution function of the electrons in their collisions with the wall and the effect of the near-wall conductivity, were discovered. The structure of the Debye layer for the case in which the coefficient of the secondary electron emission of a dielectric wall is larger than unity was investigated.