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Solar-Flare Cosmic Rays at and Beyond the Modulation Boundary

Jokipii, J. R. and Stone, E. C. (1972) Solar-Flare Cosmic Rays at and Beyond the Modulation Boundary. Journal of Geophysical Research A, 78 (16). pp. 3150-3154. ISSN 0148-0227. doi:10.1029/JA078i016p03150.

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In this letter we consider the characteristics of solar flare cosmic ray events observed beyond the postulated modulation boundary, should such a boundary exist. We point out that observations of solar flare particles at large distances from the sun provide a sensitive and precise diagnostic of any such boundary. The present consensus based primarily on indirect inferences from cosmic ray data appears to be that cosmic ray scattering effectively ceases within some 5 to 10 AU [see, e.g., Burlaga, 1967; O'Gallagher and Simpson, 1967; Ng and Gleeson, 1971; and Garrard, 1972]. Since it is expected that the solar wind continues to flow out to perhaps 50 AU [Axford, 1971], this view implies a large region of flow in which one has the classical large-scale magnetic field [Parker, 1963], but an effective absence of irregularities, which scatters the particles. Dynamic models of the solar wind producing such phenomena have been considered by Jokipii and Davis [1969] and Jokipii [1973].

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Stone, E. C.0000-0002-2010-5462
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Additional Information:Copyright © 1973 by the American Geophysical Union. (Received December 7, 1972; accepted January 26, 1973.) We acknowledge the assistance of F. Marshall in calculating the numbers in Table 1. One of us (E.C.S.) is an Alfred P. Sloan Foundation Fellow. This work has been supported in part by the National Aeronautics and Space Administration under grant NGR 05-002-160 and by the Alfred P. Sloan Foundation.
Group:Space Radiation Laboratory
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Alfred P. Sloan FoundationUNSPECIFIED
NASANGR 05-002-160
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Space Radiation Laboratory1972-06
Issue or Number:16
Record Number:CaltechAUTHORS:20140408-093304531
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ID Code:44738
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Deposited On:08 Apr 2014 21:08
Last Modified:10 Nov 2021 16:55

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