HR: 13:55h
AN: SH12B-02 INVITED     [PDF]
TI: Unusual Energetic Particle Signatures as Voyager 1 Approaches the Heliospheric Termination Shock
AU: * McDonald, F B
EM: fm27@umail.umd.edu
AF: Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 United States
AU: Cummings, A C
EM: ace@srl.caltech.edu
AF: California Institute of Technology, 1201 E. California Blvd. Mail Code 220, Pasadena, CA 91125 United States
AU: Stone, E C
EM: ecs@srl.caltech.edu
AF: California Institute of Technology, 1201 E. California Blvd. Mail Code 220, Pasadena, CA 91125 United States
AU: Heikkila, B
EM: bryant@theheikkilas.com
AF: NASA/Goddard Space Flight Center, Science and Telecommunication Branch, Greenbelt, MD 20771 United States
AU: Lal, N
EM: nand.lal@gsfc.nasa.gov
AF: NASA/Goddard Space Flight Center, Science and Telecommunication Branch, Greenbelt, MD 20771 United States
AU: Webber, W R
EM: bwebber@nmsu.edu
AF: Department of Physics and Astronomy, New Mexico State University, Las Cruces, NM 88003
AB: The heliospheric termination shock is the expected site for the acceleration of anomalous cosmic rays and the further re-acceleration of low energy particles from the inner solar system and of galactic cosmic rays. Increases in the intensity of these diverse energetic particle populations are one of the expected harbingers of Voyagers approach to the termination shock. In mid-2002 as Voyager 1 moved beyond 85 AU there began an increase of 2-3 MeV ions that remained at an unusually high level near 0.1 protons/cm$^2$ - s - sr - MeV ions for some 6 months. This event differs from any previously observed in that there is a simultaneous increase in galactic cosmic ray ions and electrons, anomalous cosmic rays and low energy ions. However the low intensity level and the spectral form of the anomalous cosmic ray component indicates that we have not reached the termination shock and the observed increase is a precursor event of the type expected as Voyager approaches the shock. Beginning in 2003.09 the unusual increases are abruptly terminated by the passage of a large interplanetary transient.
DE: 2114 Energetic particles, heliospheric (7514)
DE: 2124 Heliopause and solar wind termination
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting