The May 1997 SOHO-Ulysses quadrature

Citation
St. Suess et al., The May 1997 SOHO-Ulysses quadrature, J GEO R-S P, 105(A11), 2000, pp. 25033-25051
Citations number
30
Categorie Soggetti
Space Sciences
Journal title
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
ISSN journal
21699380 → ACNP
Volume
105
Issue
A11
Year of publication
2000
Pages
25033 - 25051
Database
ISI
SICI code
0148-0227(20001101)105:A11<25033:TM1SQ>2.0.ZU;2-7
Abstract
We present results from the May 1997 SOHO-Ulysses quadrature (SOHO-Sun-Ulys ses angle=90 degrees), near sunspot minimum. Ulysses was at 5.1 AU, 10 degr ees north of the solar equator, and off the east limb. It was also at the v ery northern edge of the streamer belt, Nevertheless, the Solar Wind Observ ations Over the Poles of the Sun instrument (SWOOPS) detected only slow, un usually smooth wind and there was no direct evidence of fast wind from the northern polar coronal hole or of mixing with fast wind. The Large-Angle an d Spectrometric Coronagraph (LASCO) images show that the streamer belt at 1 0 degreesN was narrow and sharp at the beginning and end of the 2 week obse rvation interval. but broadened in the middle. A related change in density, but not flow speed, occurred at Ulysses. Under these conditions it was pos sible to show that densities derived from the Ultraviolet Coronagraph Spect rometer (UVCS) in the lower corona are closely related to those in the sola r wind, both over quiet intervals and in transient events on the limb. Dens ity and velocity in one small transient observed by both LASCO and UVCS are analyzed in detail.