Accession Number : AD0697365

Title :   COLLISIONLESS INSTABILITIES IN CONFIGURATIONS WITH SHEARED MAGNETIC FIELDS,

Corporate Author : STANFORD UNIV CALIF INST FOR PLASMA RESEARCH

Personal Author(s) : Coppi,Bruno

Report Date : FEB 1965

Pagination or Media Count : 29

Abstract : A new set of instabilities which are fastest in the collisionless regime, being slowed down by collisions, is presented. They take place in configurations having very low pressures, sheared magnetic field and current flowing along it. These instabilities are driven by the transverse gradient of the longitudinal current and are characterized by two types of mode. Modes of one type are electrostatic and localized, having eddies of relatively short scale length, and exist for small and finite wavelengths. The other modes are non-electrostatic, non-localized and result from one which is singular in the purely hydromagnetic limit. These exist only for finite wavelengths, i.e., of the order of the width of the plasma column, in which limit they are faster than the electrostatic type of modes. The relations with known resistive modes are considered, and in particular the continuation of the tearing mode into the collisionless regime is studied. For this mode the effect of collisions is to increase the growth rate, allowing for the transfer of magnetic energy into plasma kinetic energy through line-breaking. (Author)

Descriptors :   (*PLASMA MEDIUM, STABILITY), MAGNETIC FIELDS, DISPERSION RELATIONS, CYCLOTRON RESONANCE PHENOMENA, ELECTROSTATIC FIELDS

Subject Categories : Plasma Physics and Magnetohydrodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE