Galileo plasma wave observations near Europa

In this paper we present results from the Galileo plasma wave instrument during the first two flybys of Europa, which occurred on December 19, 1996, and February 20, 1997. Strong whistler‐mode noise was observed in the vicinity of Europa during both flybys. Emission at the upper hybrid resonance frequency, f UH , and a propagation cutoff at the local electron plasma frequency, f pe , provided measurements of the local electron number density. The electron density measurements show a region of highly disturbed plasma in the vicinity of Europa with density enhancements ranging from about 30 to 100 cm −3 above the ambient Jovian magnetospheric background, which in both cases was about 80 cm −3 .