Spectroscopic constraints on models of ion-cyclotron resonance heating in the polar solar corona

Using empirical velocity distributions derived from UVCS and SUMER ultravio let spectroscopy, we construct theoretical models of anisotropic ion temper atures in the polar solar corona. The primary energy deposition mechanism w e investigate is the dissipation of high frequency (10-10000 Hz) ion-cyclot ron resonant Alfven waves which can heat and accelerate ions differently de pending on their charge and mass. We find that it is possible to explain th e observed high perpendicular temperatures and strong anisotropies with rel atively small amplitudes for the resonant waves. There is suggestive eviden ce for steepening of the Alfven wave spectrum between the coronal base and the largest heights observed spectroscopically. Because the ion-cyclotron w ave dissipation is rapid, even for minor ions like O5+, the observed extend ed heating seems to demand a constantly replenished population of waves ove r several solar radii. This indicates that the waves are generated graduall y throughout the wind rather than propagated up from the base of the corona .