Fine Structures of Planetary Radio Emissions
Abstract
One of the most striking and characteristic property of planetary radio emissions is the complexity of their continuously evolving dynamic spectrum. Ground based observations of decametric radiation from Jupiter as well as space borne measurements of those at the Earth, Saturn, Uranus and Neptune, all revealed fine structures down to the smallest observable scales, both in time and frequency. Often well organized in a hierarchy of crossed systems of fringes through the time-frequency plane, fine structures of planetary radiations are likely consequences of the coherent nature of the emission mechanism - the cyclotron maser instability -, partly because the mechanism itself predicts narrow bandwidth and beaming of the radiation, but also because radiated waves illuminate the planetary magnetospheric plasma and likely propagate through some refractive and diffractive structures before to reach the outer space. Application of classical theory of light propagation in an inhomogeneous, anisotropic optical medium allows some properties of planetary radio sources and magnetospheric plasma to be inferred.
- Publication:
-
European Planetary Science Congress 2006
- Pub Date:
- 2006
- Bibcode:
- 2006epsc.conf..468L