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Corotating particle enhancements out of the ecliptic planeWe have studied greater than 40 keV ion and electron enhancements seen at Ulysses from a series of corotating interaction regions (CIR), from mid-1992 until the end of 1993. The event intensity increased up to latitude 20 deg S; after that the ion flux maxima decreased by approximately 23%/deg while the electron maxima decreased more erratically, and more slowly, during the last half of 1993. After April, 1993, the electron increases lagged the ions by up to four days. The electron energy spectrum hardened both towards the end of the events and as the latitude went above approximately 35 deg. The electron/ion delays and the electron spectral hardening are related to the three-dimensional structure of the reverse shocks at high latitudes. The H/He ratio at approximately 0.4-1.2 MeV/nucleon decreased towards the end of each event; the mean minimum value was 3.5 +/- 0.3, lower than observed in earlier studies of CIR-associated events near the ecliptic plane. The He increases have recurred with a period of 26.0 days. There have been two phase changes: +4.3 days (February 1993) and +2.4 days (August 1993), related to changes in the coronal structure of the source regions for the high speed solar wind streams.
Document ID
19950048910
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Simnett, G. M.
(NASA Headquarters Washington, DC United States)
Sayle, K.
(University of Birmingham Birmingham, United Kingdom)
Roelof, E. C.
(Johns Hopkins University Laurel, MD, United States)
Tappin, S. J.
(University of Birmingham Birmingham, United Kingdom)
Date Acquired
August 16, 2013
Publication Date
July 1, 1994
Publication Information
Publication: Geophysical Research Letters
Volume: 21
Issue: 14
ISSN: 0094-8276
Subject Category
Space Sciences (General)
Accession Number
95A80509
Funding Number(s)
CONTRACT_GRANT: N00039-94-C-0001
Distribution Limits
Public
Copyright
Other

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