1. D. O. Gough is with the Institute of Astronomy, University of Cambridge, Cambridge, CB3 OHA UK.
2. J. W. Leibacher is with the National Solar Observatory, Tucson, AZ, USA.
3. P. H. Scherrer is with the Department of Physics, Stanford University, Stanford, CA, USA.
4. J. Toomre is with JILA, University of Colorado, Boulder, CO, USA.