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Large-Scale Structure and Termination of the Heliosphere

Published online by Cambridge University Press:  14 August 2015

W. M. Macek*
Affiliation:
Space Research Centre, Polish Academy of Sciences, Bartycka 18 A, PL-00 716 Warsaw, Poland; e-mail: macek@cbk.waw.pl

Abstract

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The question of the boundaries of the heliosphere is considered. The termination heliospheric shock should exist because the solar wind plasma flowing supersonically away from the Sun must make a transition to a subsonic flow. The heliopause is at the outermost extend of the solar wind. Beyond the heliopause lies the (very local) interstellar wind. Intensity of radio emissions at 2 to 3 kHz detected by the Voyager plasma wave instrument in the outer heliosphere can be explained provided that the electron beams generating Langmuir waves exist in the post-shock plasma due to secondary shocks in the compressed solar wind beyond the termination shock. The field strengths of Langmuir waves required to generate the second harmonic emissions are 50 – 100 μ V m-1. Alternatively, the emissions are generated in the vicinity of the heliopause. The Voyager 1 and 2 are proceeding toward a likely source region for Langmuir wave and these waves may be observed in situ in the near future.

Type
II. Joint Discussions
Copyright
Copyright © Kluwer 1998

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