A survey of Galileo plasma wave instrument observations of Jovian whistler-mode chorus

A survey of plasma wave observations at Jupiter obtained by the plasma wave instrument on board the Galileo spacecraft is presented. The observations indicate that chorus emissions are observed commonly in the Jovian magnetosphere near the magnetic equator in the approximate radial range 6 < r < 10 R-J. The survey includes almost all local times but not equally sampled in radial distance due to the spacecraft trajectory. The data suggest that chorus emissions are somewhat more intense on the dayside, but this may be a result of insufficient nightside observations. The orbit of Galileo is also restricted to +/-3 degrees of the Jovigraphic equator, but the tilt of the magnetic field permits coverage of a range of magnetic latitudes of -13 degrees < lambda(mag) < +13 degrees. The similarities of chorus emissions to terrestrial observations are a good reason to speculate that Jovian chorus emission may play a significant role in the stochastic acceleration of electrons in the radial range 6-10 R-J as recent studies indicate. These electrons may then be transported inward by radial diffusion where they are additionally accelerated to form the synchrotron radiation belt source

Equatorial electron density measurements in Saturn’s inner magnetosphere

International audienceUpper hybrid resonance emissions detected by theRadio and Plasma Wave Science (RPWS) instrument on theCassini spacecraft are used to obtain electron densities onfive equatorial orbits of Saturn at radial distances rangingfrom 3 to 9 saturnian radii (RS). The electron density profilesfor these orbits show a highly repeatable radial dependencebeyond 5 RS, decreasing with increasing radial distanceapproximately as (1/R)3.63. Inside 5 RS, the electron densityprofiles are highly variable. We show that these radialvariations are consistent with a centrifugally-drivenoutward transport of plasma from a source inside 5 RS