Ionization waves and wakes excited by an acoustic pulse

Abstract

Any sudden change of plasma parameters in originally homogeneous positive column of a low current discharge gives usually rise to a transient process, called wave of stratification. Another form of ionization waves, a periodic wake, may be noticed in neighbourhood of a permanent local disturbance of plasma homogeneity. In this work a third form of ionization waves is described, which accompanies a pulse propagating with constant velocity through plasma. After a short description of the experimental techniques a phenomenological theory of the phenomena observed in the resulting diagrams is given.