|
Detailed Reference Information |
Farrell, W.M., Curtis, S.A., Desch, M.D. and Lepping, R.P. (1992). A theory for narrow-banded radio bursts at Uranus: MHD surface waves as an energy driver. Journal of Geophysical Research 97: doi: 10.1029/91JA03143. issn: 0148-0227. |
|
We describe a possible scenario for the generation of the narrow-banded radio bursts (n bursts) detected at Uranus by the Voyager 2 planetary radio astronomy experiment. This particular radio emission is suspected to originate within the Uranian northern polar cusp region. In order to account for the emission burstiness which occurs on time scales of hundreds of milliseconds, we propose that ULF magnetic surface turbulence, generated at the frontside magnetopause, propagates down the open/closed field line boundary and mode converts to kinetic Alfv¿n waves (KAW) deep within the polar cusp. The oscillating KAW potentials then drive a transient electron stream (beam or loss cone) that creates the bursty radio emission. To substantiate these ideas, we show Voyager 2 magnetometer measurements by enhanced ULF magnetic activity at the frontside magnetopause. We then demonstrate analytically that such magnetic turbulence should mode convert deep in the cusp at a radial distance of 3RU. A condition for mode conversion from magnetic surface waves to KAW is fpc/fce<0.2, which is also a condition favorable for the generation of the R-X mode radio bursts. The fact that a similar plasma condition is required for both processes lends strong support that the active regions for mode conversion and R-X mode wave generation are one and the same. ¿ American Geophysical Union 1992 |
|
|
|
BACKGROUND DATA FILES |
|
|
Abstract |
|
|
|
|
|
Keywords
Magnetospheric Physics, Planetary magnetospheres, Magnetospheric Physics, Plasma waves and instabilities, Radio Science, Radio astronomy, Space Plasma Physics, Waves and instabilities |
|
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 |
|
|
|