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Evidence for two energetic particle sources at the termination shock

Stone, E. C. and Cummings, A. C. and McDonald, F. B. and Heikkila, B. C. and Lal, N. and Webber, W. R. (2005) Evidence for two energetic particle sources at the termination shock. In: Proceedings of the 29th International Cosmic Ray Conference. Vol.2. Tata Institute of Fundamental Research , Mumbai, India, pp. 47-48.

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During the period of unusual enhancements in the intensities of low energy ions observed by Voyager 1 beyond 85 AU, the energy spectra appear to have two components. Upstream of the termination shock, low energy ions (<10 MeV/nucleon) stream along the magnetic field and have significant variations in intensity and spectral slope. Their power law spectrum often shows no evidence of modulation at the lowest energies. This suggests a nearby source region of termination shock particles (TSPs) connected to Voyager along the interplanetary magnetic field. At intermediate energies ( ~ 10 to 60 Me V /nucleon), the helium spectrum is relatively steady and consistent with that of anomalous cosmic rays (ACRs) with modulation increasing with decreasing energy. This indicates that the ACR source is a remote region of the termination shock not connected to Voyager along the magnetic field. This distinction between the TSP and ACR sources was confirmed when Voyager 1 crossed the termination shock at 94 AU.

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Stone, E. C.0000-0002-2010-5462
Cummings, A. C.0000-0002-3840-7696
Additional Information:© 2005 Tata Institute of Fundamental Research. Provided by the NASA Astrophysics Data System. This work was supported by NASA under contract NAS7-03001.
Group:Space Radiation Laboratory
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Record Number:CaltechAUTHORS:20140827-092815858
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:48972
Deposited By: Tony Diaz
Deposited On:03 Sep 2014 14:07
Last Modified:20 Feb 2020 14:33

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