Wave dissipation by ion cyclotron resonance in the solar corona

It has recently been suggested that small-scale reconnection occurring in the chromospheric network creates high-frequency Alfven waves, and that these waves may represent the main energy source for the heating of the solar corona and generation of the solar wind. However, if these waves exist, they will be absorbed preferentially by the minor heavy ions with low gyrofrequencies, and thus it is unclear whether there is actually enough wave energy left over for the heating and acceleration of the major solar wind ions, namely protons and alpha particles, in the extended corona after the absorption by heavy ions (Cranmer 2000). We have studied this problem with the multi-fluid model presented by Tu & Marsch (2001), which includes the self-consistent treatment of the damping of the waves as well as the associated acceleration and heating of the ions. We found that if the wave power density is sufficiently large, say about 1000 nT(2) Hz(-1) at 160 Hz and 2.5 R-circle dot, then the wave absorption by a prominent minor ion such as O+5 is small, and most of the wave energy is left for absorption by protons. This occurs because the minor ions are quickly (within several gyroperiods) accelerated and then are induced to partially surfing the waves. However, if the wave power is too low, say lower than 10 nT(2) Hz(-1) at 160 Hz and 2.5 R-circle dot, then the damping of the wave power by the O+5 ions is severe, and little wave energy is left for protons.