Electron cyclotron absorption in a loss cone distribution with temperature anisotropy

Abstract

The effects of temperature anisotropy in a weakly relativistic loss cone distribution on absorption of electron cyclotron waves propagating perpendicular to the magnetic field have been studied. The relevant dielectric tensor elements are calculated in terms of the generalized Dnestrovskii functions. The absorption coefficient is determined from the anti-Hermitian part of the dielectric tensor elements. The expression for absorption coefficient contains the effects of temperature anisotropy, contributions due to finite Larmor radius to all orders, and gyroharmonic overlaps to all orders. Variations in absorption as well as loss cone instability with respect to temperature anisotropy are found both for the ordinary mode around the fundamental harmonic and the extraordinary mode around the second harmonic of electron cyclotron frequency. It is found that with the increase of density and loss cone index, the effect of temperature anisotropy is pronounced.