Chasmas in the Laboratory and in Space

Abstract

Several laboratory experiments are described in which chasmas (non-quasineutral plasmas) occur, e.g. situations related to the multipactor effect or SERD and the experiment of O’Neil. A survey is given of the theoretical work dealing with chasmas in ionizing beams, including the time dependence, e.g. the build-up phase. Several models are indicated which allow to expect astrophysical chasmas to occur, in particular in the magnetospheres. Some properties are under study. The importance is stressed of distinguishing chasmas and plasmas from e.g. observed resonances in view of inferring the correct parameters. The analysis of oscillations and instabilities is usually a very involved one, varying much from case to case, one of the reasons being that chasmas occur only under rather special circumstances.