HR: 08:45h
AN: SH41B-04    [Abstracts]
TI: Highest Intensity of Low-Energy Particles Observed in Outer Heliosphere as Voyager 1 Approaches 94 AU
AU: * Cummings, A C
EM: ace@srl.caltech.edu
AF: California Institute of Technology, Mail Code 220-47, Pasadena, CA 91125 United States
AU: Stone, E C
AF: California Institute of Technology, Mail Code 220-47, Pasadena, CA 91125 United States
AU: McDonald, F B
AF: University of Maryland, Computer and Space Sci Bldg 3245, College Park, MD 20742 United States
AU: Heikkila, B C
AF: Goddard Space Flight Center, Code 630, Greenbelt, MD 20771 United States
AU: Lal, N
AF: Goddard Space Flight Center, Code 933, Greenbelt, MD 20771 United States
AU: Webber, W R
AF: New Mexico State University, P. O. Box 30001/Dept. 4500, Las Cruces, NM 88003 United States
AB: Beginning in mid-2002, the 2-3 MeV H intensity measured by the Cosmic Ray experiment on Voyager 1 (V1) (at 85.3 AU and 33.8$^{\circ}$N) increased by a factor of $\sim$100 for $\sim$7 months, subsided for approximately 6 months, and then increased again to the highest intensities yet seen in the outer heliosphere, higher than have been recorded since solar energetic particles were observed at $\sim$15 AU in 1983. This type of activity was not observed at Voyager 2, some 18 AU closer to the Sun than is V1. The longevity of the enhanced intensities at V1 suggests that this is a durable feature of the outer heliosphere and not a transient phenomenon. The particles are thought to be coming from the termination shock of the solar wind. The anisotropy of the 3.3-7.8 MeV H particles is primarily outward from the Sun along the nominal interplanetary magnetic field line. Presumably, the field line along which the particles are streaming towards V1 intersects with the termination shock back along the direction to the Sun. We will report the latest observations of the energy spectra and anisotropies of these particles as Voyager 1 approaches 94 AU. This work was supported by NASA under contract NAS7-03001.
DE: 2104 Cosmic rays
DE: 2114 Energetic particles, heliospheric (7514)
DE: 2124 Heliopause and solar wind termination
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting