In the Sequential Accretion Theory, what mechanism caused a newly formed moon to migrate inward toward Jupiter?

Answer

Interaction with spiral density waves and gas drag

As a moon grew, its orbit generated spiral density waves in the remaining gas disk, and the interaction with these waves, combined with drag from the gas, caused the moon to migrate inward.

In the Sequential Accretion Theory, what mechanism caused a newly formed moon to migrate inward toward Jupiter?
astronomyJupitersolar systemformationmoons