Compound Effect of Alfvén Waves and Ion-cyclotron Waves on Heating/Acceleration of Minor Ions via the Pickup Process

Abstract

A scenario is proposed to explain the preferential heating of minor ions and differential streaming velocity between minor ions and protons observed in the solar corona and in the solar wind. It is demonstrated by test particle simulations that minor ions can be nearly fully picked up by intrinsic Alfvén-cyclotron waves observed in the solar wind based on the observed wave energy density. Both high frequency ion-cyclotron waves and low frequency Alfvén waves play crucial roles in the pickup process. A minor ion can first gain a high magnetic moment through the resonant wave-particle interaction with ion-cyclotron waves, and then this ion with a large magnetic moment can be trapped by magnetic mirror-like field structures in the presence of the lower-frequency Alfvén waves. As a result, the ion is picked up by these Alfvén-cyclotron waves. However, minor ions can only be partially picked up in the corona due to low wave energy density and low plasma beta. During the pickup process, minor ions are stochastically heated and accelerated by Alfvén-cyclotron waves so that they are hotter and flow faster than protons. The compound effect of Alfvén waves and ion-cyclotron waves is important on the heating and acceleration of minor ions. The kinetic properties of minor ions from simulation results are generally consistent with in situ and remote features observed in the solar wind and solar corona.

arXiv commentAccepted by Solar Physics

References in corpus (8)

• Coronal Holes
• Perpendicular Ion Heating by Low-Frequency Alfven-Wave Turbulence in the Solar Wind
• The effect of temperature anisotropy on observations of Doppler dimming and pumping in the inner corona
• Stochastic Heating, Differential Flow, and the Alpha-to-Proton Temperature Ratio in the Solar Wind
• Apparent temperature anisotropies due to wave activity in the solar wind
• Temperature anisotropy and differential streaming of solar wind ions -- Correlations with transverse fluctuations
• Ion pick-up by finite amplitude parallel propagating Alfvén wave
• Minor ion heating in spectra of linearly and circularly polarized Alfvén waves: Thermal and non-thermal motions associated with perpendicular heating

Cited by in corpus (2)

• Evolution of Alfvénic fluctuations inside an interplanetary coronal mass ejection and their contributions to local plasma heating: Joint observations from 1.0 AU to 5.4 AU
• A Parametric Investigation on the Cyclotron Maser Instability Driven by Ring-beam Electrons with Intrinsic Alfvén Waves