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Estimating Characteristics of the Heliosphere Using Anomalous Cosmic Ray Observations at Solar Maximum

Stone, E. C. and Cummings, A. C. (1999) Estimating Characteristics of the Heliosphere Using Anomalous Cosmic Ray Observations at Solar Maximum. In: The solar wind nine conference. AIP Conference Proceedings. No.471. American Institute of Physics , Melville, NY, pp. 201-204. ISBN 1563968657.

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Observations of the energy spectra of anomalous cosmic ray (ACR) oxygen were acquired in the outer heliosphere during the last solar maximum period in 1990 when the particle distributions are expected to be more nearly spherically symmetric than at solar minimum. Hence, we use a simple one-dimensional model of ACR acceleration and transport to fit the observed energy spectra at Voyagers 1 and 2 and Pioneer 10. The inferred interplanetary radial diffusion coefficient is remarkably consistent with recent theoretical estimates. The next solar maximum is expected to occur in the outer heliosphere in early 2001 when Voyager 1 will be ∼80 AU from the Sun. We predict that the intensity of ACR oxygen and helium at Voyagers 1 and 2 will be sufficiently large, and the model uncertainties sufficiently small, that it should be possible in 2001 to determine the remaining distance to the shock to within ±1 AU if the shock is within ∼5 AU, −3 to +6 AU if the shock is within ∼15 AU, and −5 to +14 AU if the shock is within ∼25 AU.

Item Type:Book Section
Related URLs:
URLURL TypeDescription
Stone, E. C.0000-0002-2010-5462
Cummings, A. C.0000-0002-3840-7696
Additional Information:© 1999 American Institute of Physics. Published online 16 June 1999. We thank W. R. Webber for supplying the Pioneer 10 data. This work was supported by NASA under contract NAS7-918.
Group:Space Radiation Laboratory
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Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory1998-08
Series Name:AIP Conference Proceedings
Issue or Number:471
Record Number:CaltechAUTHORS:20140819-132327153
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Official Citation:Estimating characteristics of the heliosphere using anomalous cosmic ray observations at solar maximum E. C. Stone and A. C. Cummings AIP Conf. Proc. 471, 201 (1999);
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:48691
Deposited By: Ruth Sustaita
Deposited On:19 Aug 2014 20:57
Last Modified:10 Nov 2021 18:34

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