Relation between shear-zone thickness, boundary layer instability and plasmoids in geomagnetosphere

Abstract

A study of the dependence of shear-zone thickness on the growth rate and frequency of Kelvin-Helmholtz instability (KHI) in the shear-zone between low latitude boundary layer (LLBL) and central plasma sheet (CPS) is carried out. It is found that the growth rate and frequency are maximum for a shear-zone of minimum thickness. The amplitude of plasma

sheet (PS) oscillation is found to be positive as the PS thickness increases and is maximum when PS thickness is 2<i>R</i>_E (1<i>R</i>_E=6378 km) for a shear-zone of minimum thickness. This perturbation generates tearing mode instability (TMI) which leads to the formation of plasmoids.