Electrostatic lofting of dust grains from the surfaces of Thebe and Amalthea

Abstract

Energetic electrons from the inner radiation belt provide significant electric charging of the surfaces of Jupiter's moons Thebe and Amalthea whose orbits are located within this radiation belt. We estimate theoretically the electric fields in the vicinity of the polar regions of Thebe and Amalthea and argue that these fields are sufficient for lofting of micron and submicron-sized dust grains from the surfaces of the moons. Thus, the lofting of charged dust grains in the electric fields can be considered as an additional source supplying dust to the gossamer rings in addition to dust ejection by micrometeoroid impacts onto the moons' surfaces. The suggested mechanism can explain qualitatively some peculiarities of the dust grain distributions within the gossamer rings.