Fundamental Technologies

Galileo Spacecraft Pages

Investigation of the Magnetosphere of Ganymede with Galileo's Energetic Particle Detector
Ph.D. dissertation by Shawn M. Stone, University of Kansas, 1999.

Chapter 6. Time-Reversed Particle Results: G2 Encounter

In Chapter 1, a few rate profiles were shown displaying the type and character of the adsorption signatures observed during the G2 encounter. It was claimed that these signatures contain valuable information about the magnetic field topology and the presence of other mechanisms such as corotational electric fields and scattering. This information can be gleaned from the time-reversed following of particles through the models of the proposed magnetic fields, discussed in Chapter 4, adding these other factors (electric fields and pitch angle scattering) to judge the range of their effects on the signatures. In Chapter 5, a set of procedures, Particle_Follow, was presented that accomplishes this task using information from Chapters 2 and 3 to set up and run through a simulated encounter, generating rate profiles like the one shown in Figure 5.11. This chapter presents the results of these tracings for the G2 encounter. The results of the G7 encounter will be presented in Appendix B for the reader to refer to during the discussion and conclusions (Chapter 8) since the presentation of and the results are similar to G2.

All rate profiles are normalized to 90 pitch within the particular spin when possible, and to the maximum rate otherwise. Due to the computational effort involved in the explicit integration of the Lorentz force equation, only three energy channels for the ions and electrons are traced, channels A2, A4, and A6 for the ions, and channels E1, E3, and F2 for the electrons. Each feature will be labeled by the UT time of the first sector of the particular spin, as was indicated in Section 5.6. Although there were many more features for the G2 encounter than are presented here, the features chosen represent the general character of the other features for the region in question. The features not included because of the length of this document are relegated to Appendix C in printed form and are referred to by various tables throughout the chapter. Also included in Appendix C is a CD which contains all the tabulated data and visualization software to produce the plots that are presented throughout this work. The interested reader is encouraged to generate these plots and even run the simulated encounters to generate their own simulated data for comparison.

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Updated 10/22/02, T. Hunt-Ward