Investigation of the Magnetosphere of Ganymede with Galileo's Energetic Particle Detector
Ph.D. dissertation by Shawn M. Stone, University of Kansas,
1999.
Copyright 1999 by Shawn M. Stone. Used with permission.
2.3.3 The Third Adiabatic Invariant
The third invariant is associated with the azimuthal drift that charged particles undergo. From the action integral Equation [2.17] and using information provided in Figure 2.8 yields

[2.29] 
where p in the direction of dl is assumed negligible since the drift velocity is typically an order of magnitude, or more, less than the particle's total velocity. Using Stoke's theorem gives

[2.30] 
where Φ is the amount of magnetic flux through the drift path. The constancy of Φ keeps the particles bouncing and drifting along the same L shell.
Figure 2.8 Conservation of the third adiabatic invariant. Magnetic flux enclosed by a particle drifting perpendicular to B and ΔB remains constant during slow changes in the magnetic field [Walt, 1994].
Next: 2.4 Pitch Angle Diffusion
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Updated 8/23/19, Cameron Crane
QUICK FACTS
Mission Duration: Galileo was planned to have a mission duration of around 8 years, but was kept in operation for 13 years, 11 months, and 3 days, until it was destroyed in a controlled impact with Jupiter on September 21, 2003.
Destination: Galileo's destination was Jupiter and its moons, which it orbitted for 7 years, 9 months, and 13 days.