Determination of the dispersion of low frequency waves downstream of a quasiperpendicular collisionless shock

摘要

A method of wave mode determination, whichwas announced in Balikhin and Gedalin, is applied to AMPTE UKS and AMPTE IRMmagnetic field measurements downstream of supercritical quasiperpendicularshock. The method is based on the fact that the relation between phasedifference of the waves measured by two satellites, Doppler shift equation, thedirection of the wave propagation are enough to obtain the dispersion equationof the observed waves. It is shown that the low frequency turbulence mainlyconsists of waves observed below 1 Hz with a linear dependence between theabsolute value of wave vector |k| and the plasma framewave frequency. The phase velocity of these waves is close to the phase velocityof intermediate waves V_int = V_acos(θ).