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The distance to the heliospheric VLF emission regionTwo major episodes of heliospheric VLF emissions near 3 kHz have been observed by the Voyager spacecraft in 1983/84 and 1992/3. This higher-frequency component is apparently triggered by solar wind transients with sufficiently large spatial extents and energies to continue to propagate as shocks in the heliosheath. Entrainment of previously unshocked material and changed flow conditions in the heliosheath both tend to slow the shock propagation. The shock evolution is not self-similar. Rather, it is intermediate to two blast-wave similarity solutions in the moving solar wind frame. In one solution the shock moves as time to the 2/3 power and in the other as time to the 4/5 power. Using these models, the shock/Forbush decrease observed at Voyager 2 in September, 1991 and the turn-on of the 1992 emission is consistent with an emission region distance of approximately 130 AU (assuming no additional slowing of the shock in the heliosheath). If the termination shock was at approximately 70 AU when the transient shock collided with it, the true distance to the source region was probably closer to approximately 115 AU.
Document ID
19950053016
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Mcnutt, R. L., Jr.
(Johns Hopkins Univ. Applied Physics Lab., Laurel, MD, US, United States)
Lazarus, A. J.
(MIT, Cambridge, MA US, United States)
Belcher, J. W.
(MIT, Cambridge, MA US, United States)
Lyon, J.
(Dartmouth College Hanover, Hanover, NH US, United States)
Goodrich, C. C.
(Univ. of Maryland, College Park, MD US, United States)
Kulkarni, R.
(Univ. of Maryland, College Park, MD US, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1995
Publication Information
Publication: Advances in Space Research
Volume: 16
Issue: 9
ISSN: 0273-1177
Subject Category
Solar Physics
Accession Number
95A84615
Funding Number(s)
CONTRACT_GRANT: NAGW-1550
Distribution Limits
Public
Copyright
Other

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