We thank T. Metcalf and S. McClymont for helpful discussions in early stages of this work. L.G.B. thanks the staff at IFA for their hospitality. Data used here from Mees Solar Observatory, University of Hawaii, are produced with the support of NASA grant NAG 5-4941 and NASA contract NAS8-40801. We thank the Yohkoh team for SXT/Yohkoh data. We acknowledge financial support from the Max Planck Institut für Extraterrestrische Physik, and from CONICET (Argentina) and NSF (USA) through the CONICET-NSF agreement. We acknowledge financial support from ECOS (France) and ANPCYT (Argentina) through their cooperative science program (A97U01).
C.H.M. and M.G.R. are members of the Carrera del Investigador Científico , CONICET.
© European Southern Observatory (ESO) 2000
Online publication: December 11, 2000