Energetic Particle Observations Near the Termination Shock
- Applied Physics Laboratory, Johns Hopkins University, Johns Hopkins Rd, Laurel, MD, 20723 (United States)
- Department of Physics, University of Maryland, College Park, MD, 20742 (United States)
The most recent data from Voyager 1 (V1) show that a second event (TS2), apparently associated with the termination shock (TS), is in progress, with spectral characteristics similar to the energetic particle increase observed from 2002.4-2003.1 (TS1). We concentrate on the pressure, composition, and anisotropy profiles of TS1. The magnetic field pressure is significantly smaller than the particle pressure perpendicular to the interplanetary magnetic field (IMF) in the 40-4000 keV range. The composition during the interplanetary shock event (ISE) observed by V1 during 1991 is drastically different from that during TS1 (C/O {approx}0.2 for ISE, {approx}0.02 for TS1). The dominant anisotropy during TS1 is azimuthally in the outward direction for a Parker spiral field, suggesting a source inward of the spacecraft, while the radial anisotropy is consistent with zero (-0.024 {+-} 0.02), implying a slow (<50 km/s) plasma flow speed. We conclude that the totality of the data is consistent with V1 being in the heliosheath during TS1.
- OSTI ID:
- 20633016
- Journal Information:
- AIP Conference Proceedings, Vol. 719, Issue 1; Conference: 3. international IGPP conference on physics of the outer heliosphere, Riverside, CA (United States), 8-13 Feb 2004; Other Information: DOI: 10.1063/1.1809510; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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