Small-scale dynamic structures in low-pressure microwave discharges

Abstract

Three different physical models of the nonlinear stage of plasma-resonance ionization instability (PRII) of a microwave discharge in fields with different configurations have been studied analytically and numerically. The regimes of 1-D sharpening of profiles of the field amplitude and plasma density, which are described by the self-similar solution of the diffusion equation with a nonlinear source, have been investigated. We describe the scenarios for 2-D evolution of a breakdown wave in an inhomogeneous gas (or in a focused wave beam with the given ray tubes), which, because of instability development, breaks down into separate plasmoids inside which “active regions” with increased values of the field amplitude and ionization rate are generated. The processes of formation of self-sustained plasma waveguides and adiabatic transformation of the fast wave mode into the slow one during gas breakdown in an inhomogeneous field of a p-polarized wave are simulated on a computer.