Test particle correlation by a whistler wave in a nonuniform magnetic field

Computer simulations of the correlation in phase of test electrons in a monochromatic whistler wave propagating along a nonuniform external magnetic field are presented. The behavior of resonant electrons depends on an inhomogeneity ratio R, which defines the external field gradient in relation to the wave amplitude. In the case ‖R‖<1, where electron trapping is possible, a hole (or an island) of particles is found to occur in phase plots of the distribution function. This causes the appearance of a transverse current coherent with the wave, which is most intense for ‖R‖≲0.6. The significance of these results to magnetospheric propagation of a quasi-monochromatic whistler pulse is discussed.