On generation of high-frequency Alfvén waves in the solar corona

We discuss a source for high-frequency Alfven waves, associated with twisted magnetic loops emerging on the solar surface and reconnecting with the open field. We identify the loops with the ephemeral regions (small-scale bipoles) observed by ground-based instruments and by SOHO. To characterize the loops we employ the concept of a minimum energy state for topologically complex fields. Our estimates of the power that can be released and the range of wave frequencies marginally agree with models of coronal heating and acceleration of the solar wind by high-frequency Alfven waves. We suggest that severe requirements on the upper-bound frequency, used in these models, can be relaxed by taking into account the energy released due to reconnections within magnetic loops whose footpoints are twisted by surface convective motions. This presentation updates our more extended discussion of the source of coronal heating (1).