HR: 0800h
AN: SM51B-0362    [Abstracts]
TI: Bump on the tail instability in mirror stable space plasmas
AU: * Pokhotelov, O A
EM: o.a.pokhotelov@sheffield.ac.uk
AF: Automatic Control and Systems Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD United Kingdom
AU: Balikhin, M A
EM: balikhin@acse.shef.ac.uk
AF: Automatic Control and Systems Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD United Kingdom
AB: A fully kinetic theory of mirror type modes in non-Maxwellian space plasmas accounting for the arbitrary ion Larmor radius effect (FLR) is developed. A general mirror mode dispersion relation for the arbitrary velocity distribution in a fully kinetic limit is obtained. The analyses of this dispersion relation shows that in a fully kinetic limit it describes two different instabilities. The first one corresponds to the classical mirror instability which growth rate attains the maximum value at the wavelengths of the order of the ion Larmor radius. In addition, we found that if plasma is mirror stable, i.e. when the condition for the mirror instability is not satisfied, the plasma can still be unstable. The instability in this case arises in the presence of the bump on the tail of the ion distribution function and FLR effects. This new instability which we term as bump on the tail instability occurs for the wavelengths shorter then the ion Larmor radius. A compact expression for the instability growth rate is obtained. The results of the theory are compared with the existing satellite observations.
DE: 7851 Shock waves
DE: 7871 Waves and instabilities
DE: 2728 Magnetosheath
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting