Magnetic induction in spherical geometry: Sounding Jupiter’s moons

In the first part of the lecture, the basic theory of magnetic induction is derived from Maxwell’s equations. A solution for the induction equation is then derived for a spherical layer of a solid state or fluid conductor at rest which is exposed to a time-variable spatially homogeneous magnetic field.

In the second part, we show how this magnetic induction is used to probe sub-surface conductive layers inside Jupiter’s large Galilean moons. In the end, observations of auroral emissions from Jupiter’s moon Ganymede are shown, which are affected by the magnetic induction inside the moon. Ganymede’s aurora provides a unique screen for the phenomenon of magnetic induction.