Ion-cyclotron waves in Solar Coronal Hole

TL;DR

This study models ion-cyclotron wave propagation in Solar Coronal Holes, revealing that interplume lanes are more effective sources of fast solar wind due to resonance processes, with implications for understanding solar wind acceleration.

Contribution

It introduces a kinetic theory model considering gradients in physical parameters along and across magnetic fields, providing a more comprehensive analysis of ion-cyclotron wave behavior in coronal holes.

Findings

Resonance processes are more effective in interplume lanes.

Interplume lanes are primary sources of fast solar wind.

The model accounts for parameter gradients in multiple directions.

Abstract

We investigate the effect of the Plume/Interplume Lane (PIPL) structure of the solar Polar Coronal Hole (PCH) on the propagation characteristics of ion-cyclotron waves (ICW). The gradients of physical parameters determined by SOHO and TRACE satellites both parallel and perpendicular to the magnetic field are considered with the aim of determining how the efficiency of the ICR process varies along the PIPL structure of PCH. We construct a model based on the kinetic theory by using quasi-linear approximation. We solve the Vlasov equation for O VI ions and obtain the dispersion relation of ICW. The resonance process in the interplume lanes is much more effective than in the plumes, agreeing with the observations which show the source of fast solar wind is interplume lanes. The solution of the Vlasov equation in PIPL structure of PCH, the physical parameters of which display gradients along and perpendicular direction to the external magnetic field, is thus obtained in a more general form than the previous investigations.