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The Physical Significance of 'Shifted' Gradients and the Location of the Solar Wind Termination Shock

Stone, E. C. and Cummings, A. C. and Webber, W. R. (1991) The Physical Significance of 'Shifted' Gradients and the Location of the Solar Wind Termination Shock. In: Proceedings of the 22nd International Cosmic Ray Conference. Vol.3. Institute for Advanced Studies , Dublin, Ireland, pp. 386-389.

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We use observations of anomalous cosmic-ray (ACR) oxygen from the cosmic-ray experiments on the Voyager 2 (V2) and Pioneer IO (PIO) spacecraft during 1985-1988 to investigate the physical significance of the "shifted" radial gradient The "shifted" gradient is computed by comparing fluxes measured at different times at the two spacecraft to "correct" for the propagation delay of solar modulation. We use a simple model of particle propagation in which the flow is inwards along the wavy neutral sheet to suggest that for qA < 0 near solar minimum conditions the "shifted" gradient is a measure of the gradient near the solar wind termination shock. This simple model leads to an estimate of the location of the termination shock at 55(+9/-5) AU, suggesting that the shock could be encountered within this decade.

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Stone, E. C.0000-0002-2010-5462
Cummings, A. C.0000-0002-3840-7696
Additional Information:© Dublin Institute for Advanced Studies. Provided by the NASA Astrophysics Data System. Under the auspices of the International Union of Pure and Applied Physics (IUPAP). We are grateful to T. Hoeksema for providing the neutral sheet tilt data. This work was supported in part by NASA under contract NAS7-918 and grant NAGW-1919.
Group:Space Radiation Laboratory
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Space Radiation Laboratory1991-11
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ID Code:49979
Deposited By: Deborah Miles
Deposited On:29 Sep 2014 16:09
Last Modified:20 Feb 2020 14:33

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