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Detailed Reference Information |
Armstrong, J.W., Coles, W.A. and Rickett, B.J. (2000). Radio wave scattering in the outer heliosphere. Journal of Geophysical Research 105: doi: 10.1029/1999JA900471. issn: 0148-0227. |
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The Voyager 1 and 2 plasma wave instruments have observed low-frequency (1.5--4 kHz) radio waves apparently generated near the heliopause. The waves are found in two distinct bands. Power at the lower frequencies centered on 1.78 kHz shows no modulation when the spacecraft is rolled about the Earth-spacecraft line, indicating that the radiation is isotropic. Power in the higher band centered on 3.11 kHz shows roll modulation as high as 60%, indicating that the source of the radiation is quite compact, subtending an angle <1 rad at the spacecraft. Simple estimates of the scattering of 3.11 kHz radiation from electron density fluctuations indicate that, if the radiation had originated from the distance of the heliopause, the scattering would be so large that no roll modulation should be observed. Here we show that these earlier scattering estimates were too high because they ignored the latitude variation of scattering and the inner scale of the electron density fluctuation spectrum. With these two effects properly included, the expected scattering is consistent with the observations and the postulate that the radiation originates from near the nose of the heliosphere. ¿ 2000 American Geophysical Union |
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Abstract |
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Keywords
Interplanetary Physics, Heliopause and solar wind termination, Interplanetary Physics, MHD waves and turbulence, Interplanetary Physics, Plasma waves and turbulence, Interplanetary Physics, Solar wind plasma |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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