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

TL;DR

This study investigates how kinetic Alfven waves are converted and behave across the solar transition region, revealing enhanced electric fields and plasma acceleration effects.

Contribution

It provides a detailed two-fluid model analysis of wave coupling, electric field enhancement, and energy flux re-direction in the transition region.

Findings

Electric displacement fields are enhanced up to two orders across the transition region.

Kinetic Alfven waves couple with electrostatic ion sound waves via transverse wavenumber.

Reflected waves induce a ponderomotive force that accelerates plasma particles upward.

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.