The Ulysses solar wind plasma experiment observed a series of interplanetary shocks and coronal mass ejections (CMEs), the latter evidenced by counterstreaming electrons and a variety of ion signatures, during March and April 1991. A striking sequence was observed near 2.5 AU from March 23 through April 2, with the second of two counterstreaming events lasting 6.4 days. We summarize the plasma observations for these features, suggesting that the second counterstreaming period may be two juxtaposed CMEs. The relationship between the events observed at Ulysses, ∼60° east of Earth in ecliptic longitude, and those causing a geomagnetic storm on March 24, is unclear.
All Science Journal Classification (ASJC) codes
- Earth and Planetary Sciences(all)