Investigation of the Structure and the Plasma Parameters in a "Critical Velocity" Rotating Plasma

Abstract

Abstract The structure and the plasma parameters of a rotating plasma showing Alfvén's critical velocity were investigated for the first time by means of Langmuir probes. It was demonstrated that the occurrence of the critical velocity is causally connected with the formation of a spoke structure. The electron temperature and the plasma density were determined with local resolution by which a detailed balance concerning the plasma density and the current transport became possible. The importance of turbulent electron heating for rapid ionization at the critical velocity is emphasized. In this process the modified two-stream-instability obviously plays an outstanding role.