Origin of ultraviolet emission source in the Jovian ionosphere at the feet of the Io flux tube

A model for an explanation of far ultraviolet (FUV) emissions observed from the Io flux tube footprints at the Jovian ionosphere is presented. An acceleration of electrons and ions of the ionospheric plasma up to sufficient energies for an effective excitation of H2 Lyman and Werner bands is proposed. The neutral particles within the Jovian ionosphere are excited due to their collisions with the charged particles relatively moving to the neutrals in the ionospheric plasma. The motion is induced by the Ampère force which arises due to the interaction between the electric current flowing within the Io magnetic flux tube and its own specific magnetic field. It is established that only a sufficiently strong field‐aligned current is capable of providing the required velocity of the relative motion. Our estimates show that in principle the proposed mechanism can provide the level of FUV emissions observed from the Io flux tube footprints.