Dust detection in the Saturn rings by the Cassini spacecraft

We present an investigation of the dust distribution in the Saturn’s rings based on hypervelocity dust impacts observed by the Cosmic Dust Analyzer (CDA) and the Radio and Plasma Wave Science (RPWS) instrument on board the Cassini spacecraft. The dust impacts create spiky signals in the electric field waveforms that are used to determine profiles of impact count rate, dust mass, and evaluated wave power spectral density (PSD) during the ring crossings. Information about the dust composition and velocity is extracted from the available CDA data. The calculated profiles of the ring crossings are then employed to determine the width of the rings and their displacement from the equatorial plane as a function of radial distance from Saturn center in the range from 2.46 to 5.85 Rs. This dependence shows a significant enhancement of the dust density within the Janus/Epimetheus ring region at 2.46 — 2.56 Rs and at the Enceladus orbit at 3.95 Rs. The resolved dust impact rate and PSD profiles show a good agreement in the width and displacement of the investigated rings. Relations are found between the PSDs and the number of dust impact signals, and their amplitudes present in the waveform. Our results show that the calculated PSDs have strong dependence on the relative velocity between dust and spacecraft. The observed one order PSD variation at a fixed radial distance for a constant relative dust-spacecraft velocity is probably related to the variability of the dust population in the examined Janus/Epimetheus ring.