[P-CG19] Planetary Magneto-Ionosphere &Atmosphere

[PCG19-P08] Detection of dust impact signals by the Electric Field Instrument onboard the ARTEMIS satellite around the Moon

*Satoshi Kurita¹, Takaramoto Kouta¹, Hirotsugu Kojima¹ (1.Research Institute for Sustainable Humanosphere)

Keywords:Moon, dust, ARTEMIS

We report on observations of hypervelocity dust particles impacting the ARTEMIS satellites orbiting around the Moon, using data from the ARTEMIS/Electric Field instrument(EFI). Hypervelocity dust impacts on spacecraft produce transient clouds of plasma generated by the impact vaporization, which are observed by electric field instruments onboard the spacecraft as large amplitude voltage spikes with a short duration. The typical timescale for the spikes is an order of milliseconds, and amplitude ranges from a few to hundreds of mV/m [Gurnett et al., 1983, Kurth et al., 2006, Meyer-Vernet et al., 2009, Zaslavsky et al., 2012]. The ARTEMIS satellites orbit around the Moon with a highly elliptical orbit from the altitude range from a few hundred km to above 10,000 km. EFI consists of four electric field sensors in the satellite spin plane, two electric field sensors along the spin axis, and the receiver measuring the frequency range from DC to 4 kHz. Individual sensor voltages relative to the spacecraft potential for 8 seconds are available about three times per day, with a sampling rate of 4 kHz. This dataset is useful to find the voltage pulses induced by the hypervelocity dust impacts. We investigated the high-time resolution voltage dataset and found voltage spikes, which are likely to be generated by the dust impacts. The voltage pulses are observed regardless of the distance from the Moon, suggesting that the majority of the events are caused by the impact of interplanetary dust (IPD) and interstellar dust (ISD) rather than the moon-originated dust particles. The mass and impact velocity of the dust particles are estimated from the measured amplitude of the voltage in cooperation with the result of the laboratory experiment. The estimated mass and impact velocity agree well with the properties of IPD and ISD reported in previous studies, indicating that the dust particles impacting the ARTEMIS satellites mostly originate from interplanetary and interstellar space. Our results give the upper limit on the height moon-originated dust particles can reach and the usefulness of detecting dust particles with spaceborne electric field instruments.