On the absorption of Alfven waves in the solar corona

The collisional damping of Alfven waves propagating outward in the solar corona is considered. The absorption is shown to be maximum in regions where the wave frequency is close to the ion-ion collision frequency. The optical depth for Alfven waves with periods of about 5 min is of the order of unity. The spatial distribution of coronal Alfvenic heating is considered. It is shown that this heat source is maximum at heliocentric distances of about 1.5R., and that the characteristic width of the region of energy release is of the order of 0.1R. or larger.