WAVE-PARTICLE MOMENTUM EXCHANGE RATE FROM ELECTROSTATIC INSTABILITY IN THE PLASMA SHEET BOUNDARY LAYER

The second-order theory of ion beam-density gradient drift instabilities on the outer edge of the inhomogeneous plasma sheet boundary layer (PSBL) are presented in this paper. The calculations for the second-order momentum exchange rate show that the field-aligned momentum for the cold and warm beam ions in the model may be decreased by electrostatic waves which result from ion beam-density gradient drift instabilities. These results are very helpful in understanding the isotropization and thermalization of the plasma on the outer edge of the PSBL.