Galileo Spacecraft Pages
EPD Highlights During the Galileo Mission
Source: D. Williams, EPD Team Meeting, March 1998
- Discovery of intense, bidirectional, field-aligned energetic electron beams
streaming along the Io fluxtube. If they fill the Io fluxtube, they carry sufficient
energy to Jupiter's atmosphere to generate aurorae at the foot of the Io fluxtube.
- Use of
energetic electron angular distributions observed at Ganymede to measure the
surface magnetic field of Ganymede and verify its internal field.
of energetic electrons trapped in Ganymede's magnetic field, identifying closed
Ganymede magnetic field lines and further substantiating the concept of a
Ganymede magnetosphere. Note that Ganymede's magnetosphere is larger than
that of Mercury.
- First measurement of the amount of pitch angle scattering
that occurs for energetic electrons during their travel from Ganymede to the
near-Jupiter mirror point and back. The energy-dependent pitch angle
diffusion coefficient was extracted from the data.
- First possible
observation of fluxtube interchange in the Io torus, providing a measure of
particle transport through this region and into the Jovian magnetosphere.
- Measurement of heavy ion intensities in Io's torus show that they are
significantly lower than at the time of Voyager, some 17 years ago. This
decrease in heavy ion intensities provides an explanation for differences seen
in Jovian aurorae between the Voyager and Galileo eras.
- Discovery of
energetic particle injection events in Jupiter's inner magnetosphere that are
similar to particle injections at earth during magnetic substorm events.
Dispersion features are seen in both electrons and ions, implying a common
injection region followed by particle drift superimposed on corotation effects.
Sputtering and surface erosion effects resulting from energetic ion bombardment
of Europa and Ganymede.