A search for the coronal origins of fast solar wind streams during the Whole Sun Month period

A. J. Lazarus, J. T. Steinberg, D. A. Biesecker, R. J. Forsyth, A. B. Galvin, F. M. Ipavich, S. E. Gibson, A. Lecinski, D. M. Hassler, J. T. Hoeksema, P. Riley, L. Strachan, Jr., A. Szabo, R. P. Lepping, K. W. Ogilvie, and B. J. Thompson

MIT, Cambridge, MA


Several solar wind streams having speeds in excess of 500 km/s were observed from the Wind, SOHO, and Ulysses spacecraft during the Whole Sun Month (WSM) August 10 to September 8, 1996. By assuming that the solar wind observed in the trailing edge of a high speed stream propagates radially outward from the Sun at constant speed, an apparent heliographic longitude for its source can be determined. We compare the sources determined in that manner with observations from instruments on the SOHO spacecraft. We present data covering Carrington Rotations 1912 and 1913, which overlap the Whole Sun Month period. There are two groups of high-speed (>500 km/s) streams: a well-defined stream structure at Carrington longitudes near 320° and another set of streams in the longitude range from 0° to 170° . The magnetic field azimuthal angle observations at 1 AU from Wind show that all the streams are associated with outward fields near the Sun. That field direction is consistent with the sources of the faster-streams being above the neutral sheet as determined from the Wilcox Solar Observatory magnetic field source surface synoptic plot.

Proceedings of the Fifth SOHO Workshop, ESA SP-404, 511, 1997