Transition region-induced kinetic Alfven wave conversion. Electric displacement field

Abstract

The transition region is a thin inhomogeneous region where Alfven waves' energy fluxes generated elsewhere in the solar atmosphere are effectively converted. Large-scale kinetic Alfven wave propagations, transmission, and reflection processes across the transition region are examined. The two-fluid model is adopted, and a study is conducted of how the kinetic Alfven wave electric displacement field changes across the transition region. The analysis outcomes are: the kinetic Alfven wave and electrostatic ion sound waves are coupled by the transverse wavenumber; wave electric field components (normal to the transition region) become enhanced up to two orders; the energy fluxes of transmitted kinetic Alfven waves are re-directed almost horizontally along the transition region, an evanescent electric field zone of enhanced intensity is induced tightly beyond the transition region; the ponderomotive force that emerges in that zone due to the reflected kinetic Alfven waves accelerates plasma particle upwards compared to their initial energy in the upper chromosphere.