Assessment of mechanisms for Jovian synchrotron variability associated with comet SL‐9

Abstract

The impact of comet SL9 with Jupiter induced a number of variations in Jupiter's synchrotron radiation; including a 20–30% increase in emission intensity, spectral changes, and a possible broadening in the latitudinal distribution of the emission. Here we consider the consequences of three potential mechanisms for inducing such effects; namely electron acceleration, radial diffusion and pitch‐angle scattering. While none of the processes can be ruled out as insignificant, we show that pitch‐angle scattering is consistent with all of the available radio frequency data and demonstrate that this could be due to realistic enhanced amplitudes of cyclotron resonant whistler‐mode waves associated with the comet impacts. We suggest that the waves could result from electrical storm activity or be excited by natural instabilities of the electron distribution in Jupiter's radiation belts.