Generation of kinetic Alfven waves by mirror instability

The perturbed velocity deltaV and deltaB of mirror waves are usually coplan ar with the wave vector k and background magnetic field Bo. However, recent satellite observations and hybrid simulations show the presence of extra n on-coplanar components in deltaV and deltaB associated with mirror waves. I n this paper, we show from hybrid simulations that in the nonlinear stage o f mirror instability, the noncoplanar perturbations in deltaV and deltaB of high wavenumber modes can be decoupled from mirror waves and generate a pa ir of kinetic Alfven waves propagating in opposite direction. The Hall effe ct can explain the excitation of noncoplanar components in mirror waves. Th ese kinetic Alfven waves can be generated in the dayside magnetosheath, pro pagate tailward along the magnetic field lines draped around the magnetopau se, and contribute to the plasma transport into magnetosphere.