Abstract
Intrinsic magnetic field of Jovian icy satellite Ganymede is discovered by Galileo spacecraft. This magnetic field is considered to be originated by self-excited dynamo in Ganymede's metallic core. On the other hand, Europa does not have large intrinsic magnetic field even though many tectonic features implying endogenic activity exist on the surface. Considering that the terrestrial Moon that has same size as the rock-metal interior of Ganymede are inactive and endogenic activity ceased in very early stage, whether present Ganymede's thermal state can drive the dynamo activity is not definite. We perform numerical simulation about thermal history of the core in Ganymede, and evaluate the temperature in the metallic core and the driving of dynamo activity.
