Journal article
Foreshock theories for the outer heliospheric radio emissions
Advances in space research, Vol.13(6), pp.205-208
06/01/1993
DOI: 10.1016/0273-1177(93)90410-D
Abstract
Progress made on recent theories for the 2 – 3 kHz radio emissions in the outer heliosphere is summarized. The theories involve radiation produced near ƒp and/or 2ƒp, by nonlinear processes involving Langmuir waves, when solar wind density enhancements enter the foreshock region sunwards of the termination shock. Two classes of events have been detected by Voyager: transient drifting emissions and a relatively continuous 2 kHz component. Foreshock theories for both types of emissions are presented and discussed, with emphasis placed on the role of density inhomogeneities. Our conclusions are as follows. (1) The levels and characteristics of the transient events are consistent with the expectations of the foreshock theory. The source may be located outside 50 AU. (2) The higher foreshock wave levels and enhanced density regions associated with stream-stream interactions in the outer heliosphere provide rationales for McNutt's trigger hypothesis. (3) A foreshock theory cannot easily account for the 2 kHz component's almost constant frequency range. Explanations in terms of steady density enhancements or an alternative source region and/or emission mechanism should be sought.
Details
- Title: Subtitle
- Foreshock theories for the outer heliospheric radio emissions
- Creators
- Iver H. Cairns - University of IowaWilliam S. Kurth - University of IowaDonald A. Gurnett - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Advances in space research, Vol.13(6), pp.205-208
- Publisher
- Elsevier Ltd
- DOI
- 10.1016/0273-1177(93)90410-D
- ISSN
- 0273-1177
- eISSN
- 1879-1948
- Language
- English
- Date published
- 06/01/1993
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455550702771
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