Ion cyclotron wave dissipation in the solar corona: The summed effect of more than 2000 ion species

In this paper the dissipation of ion cyclotron resonant Alfven waves in the extended solar corona is examined in detail. For the first time, the wave damping arising from more than 2000 low-abundance ion species is taken into account. Useful approximations for the computation of coronal ionization equilibria for elements heavier than nickel are presented. Also, the Sobolev approximation from the theory of hot-star winds is applied to the resonant wave dissipation in the solar wind, and the surprisingly effective damping ability of "minor" ions is explained in simple terms. High-frequency (10-10,000 Hz) waves propagating up from the base of the corona are damped significantly when they resonate with ions having charge-to-mass ratios of about 0.1, and negligible wave power would then be available to resonate with higher charge-to-mass ratio ions at larger heights. This result confirms preliminary suggestions from earlier work that the waves that heat and accelerate the high-speed solar wind must be generated throughout the extended corona. The competition and eventual equilibrium between wave damping and wave replenishment may explain observed differences in coronal O VI and Mg X emission line widths.