Properties of ion-cyclotron waves in the open solar corona

TL;DR

This paper investigates ion-cyclotron waves in the open solar corona using a WKB linear perturbation analysis within a collisionless multi-fluid model, focusing on wave propagation and plasma heating in coronal holes.

Contribution

It introduces a detailed ray tracing approach to study ion-cyclotron wave behavior in non-uniform coronal plasma with alpha particles included.

Findings

Wave ray paths are computed in non-uniform plasma.

Ion-cyclotron wave properties vary spatially in coronal funnels.

Results support wave-based plasma heating mechanisms.

Abstract

Remote observations of coronal holes have strongly implicated the resonant interactions of ion-cyclotron waves with ions as a principal mechanism for plasma heating and acceleration of the fast solar wind. In order to study these waves, a WKB (Wentzel-Kramers-Brillouin) linear perturbation analysis is used in the work frame of the collisionless multi-fluid model where we consider in addition to the protons a second ion component made of alpha particles. We consider a non-uniform background plasma describing a funnel region in the open coronal holes and we use the ray tracing Hamiltonian type equations to compute the ray path of the waves and the spatial variation of their properties.