Three-fluid 2.5D MHD models of waves in solar coronal holes and the relation to SOHO/UVCS observations

Abstract

The physical properties of the minor ions in the corona provide clues on the coronal heating and solar wind acceleration mechanism. Recent observations show that protons and minor ions are hot (Tp>106 K, Ti>108 K) and anisotropic in coronal holes. A possible cause of the large perpendicular motions is unresolved Alfvenic fluctuations in the solar wind. Using the three-fluid 2.5D MHD model I have shown that the unresolved Alfvenic fluctuations lead to apparent proton temperature and anisotropy consistent with UVCS observations. I show the calculated dependence of the apparent kinetic temperatures of protons and O5+ ions with heliocentric distance and compare the results to the UVCS observations.