Solar wind penetration into dusty magnetospheres creates electrostatic waves and structures

The low frequency electrostatic perturbations have been investigated in a bi-ion plasma in the background of static dust. It is shown that the field aligned shear flow of both the ions produces low frequency electrostatic instabilities and creates nonlinear structures, the double layers, and the solitons. The general theoretical model is applied to the magnetospheres of Jupiter (with positively charged dust) and Saturn (with negatively charged dust), which have oxygen ions in addition to protons. This model predicts the existence of extremely low frequency electrostatic waves with real frequencies of the order of a millihertz (mHz) to several mHz, and this range of frequencies has been reported in literature for these plasma environments. The estimated width of the nonlinear structures varies from a few hundred meters to a few kilometers. These structures are similar to those observed in the oxygen and oxygen hydrogen plasmas in Earth's upper ionosphere that is free from dust.