Arnaud Zaslavsky - The interplanetary dust cloud observed in-situ by space based radio antennas

The interplanetary dust cloud observed in-situ by space based radio antennas

Abstract: The talk will present an introduction on the physics of the interplanetary "zodiacal cloud" of dust, on the in-situ radio detection methods, and some of the results that this technique offered in the last decade. Impacts of dust grains on spacecraft are known to produce impulsive signals in the voltage recorded at the terminals of electric antennas. Such signals have been recorded by the radio and plasma wave frequency and time-domain analyzers aboard several missions, from Voyager to the recently launched Solar Orbiter and Parker Solar Probe spacecraft, and shall be used for the future Comet Interceptor mission. These pulses result from the production of free electric charges by impact ionization after a dust grain hits the spacecraft. The electrostatic influence of these charges onto the conducting spacecraft material, as well as the electric currents induced by their dynamics, will change the spacecraft and antennas potential and produce the measured voltage transients. Magnetic field transients have also been lately observed in the search coil data of Solar Orbiter and Parker Solar Probe space missions. The large surface area of detection provided by the technique has allowed for extensive statistical studies of the impacts with a continuous coverage on several decades. These studies opened an interesting observation window on the interplanetary dust population. Novel results include the measurements of nano-meter sized dust by the STEREO mission, the measurement and survey of the variation of the interstellar dust flux at 1 AU by Wind and STEREO, as well the measurement of the beta-meteoroids population density and mean velocity with Solar Orbiter and Parker Solar Probe.