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Precursors To Interstellar Shocks of Solar Origin

Gurnett, D. A. and Kurth, W. S. and Stone, E. C. and Cummings, A. C. and Krimigis, S. M. and Decker, R. B. and Ness, N. F. and Burlaga, L. F. (2015) Precursors To Interstellar Shocks of Solar Origin. Astrophysical Journal, 809 (2). Art. No. 121. ISSN 0004-637X. doi:10.1088/0004-637X/809/2/121.

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On or about 2012 August 25, the Voyager 1 spacecraft crossed the heliopause into the nearby interstellar plasma. In the nearly three years that the spacecraft has been in interstellar space, three notable particle and field disturbances have been observed, each apparently associated with a shock wave propagating outward from the Sun. Here, we present a detailed analysis of the third and most impressive of these disturbances, with brief comparisons to the two previous events, both of which have been previously reported. The shock responsible for the third event was first detected on 2014 February 17 by the onset of narrowband radio emissions from the approaching shock, followed on 2014 May 13 by the abrupt appearance of intense electron plasma oscillations generated by electrons streaming outward ahead of the shock. Finally, the shock arrived on 2014 August 25, as indicated by a jump in the magnetic field strength and the plasma density. Various disturbances in the intensity and anisotropy of galactic cosmic rays were also observed ahead of the shock, some of which are believed to be caused by the reflection and acceleration of cosmic rays by the magnetic field jump at the shock, and/or by interactions with upstream plasma waves. Comparisons to the two previous weaker events show somewhat similar precursor effects, although differing in certain details. Many of these effects are very similar to those observed in the region called the "foreshock" that occurs upstream of planetary bow shocks, only on a vastly larger spatial scale.

Item Type:Article
Related URLs:
URLURL TypeDescription
Stone, E. C.0000-0002-2010-5462
Cummings, A. C.0000-0002-3840-7696
Krimigis, S. M.0000-0003-2781-2386
Burlaga, L. F.0000-0002-5569-1553
Additional Information:© 2015 The American Astronomical Society. Received 2015 April 29; accepted 2015 July 14; published 2015 August 14. The research at the University of Iowa was supported by NASA through contract 1279980 with JPL. The research at Caltech was supported by NASA contract NNN12AA012, and the research at the Johns Hopkins Applied Physics Laboratory was supported by the Voyager Interstellar Mission under NASA contract NNN06AA01C. The research at the Catholic University of America was supported in part by NASA grant NNX12AC63G, and the research at Goddard Spaceflight Center was supported by NASA contract NNG14PN24P.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Subject Keywords:cosmic rays – local interstellar matter – shock waves – Sun: heliosphere
Issue or Number:2
Record Number:CaltechAUTHORS:20151020-083336736
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:61304
Deposited By: Tony Diaz
Deposited On:20 Oct 2015 18:50
Last Modified:10 Nov 2021 22:47

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