Prompt structuring of a plasma expanding in an external magnetic field.

Large amplitude flute-like modes on plasmas expanding in external magnetic fields have been observed in both space and laboratory experiments. In this paper we review relevant experimental, theoretical, and numerical research with particular emphasis on the work that has been carried out at Los Alamos. Theoretical research on the diocotron instability and both the electrostatic and electromagnetic aspects of the lower-hybrid drift instability is summarized. Simulation results based on a hybrid code with finite electron mass, an electrostatic particle code, and an electromagnetic particle code are also described. We conclude that the lower hybrid drift instability rather than the diocotron instability is the likely source of the flute modes but that nonlinear effects must be invoked to explain the wavelengths of the observed structures. A number of unresolved issues related to the theory and experiments are also discussed.