10:30 AM - 10:45 AM
[PEM25-07] Classification of ULF waves observed by ARTEMIS around the Moon in the solar wind
The two probes are orbiting around the Moon in the ecliptic plane at selenocentric distances〜1.1-12 lunar radii since July 2011. We analyze the time series of the magnetic field vectors sampled in 4 Hz by the fluxgate magnetometer (FGM) in the fast survey mode. In consequence of comprehensive analyses, we identify four types of ULF waves: 1) broadband electromagnetic noise, 2) 1 Hz whistlers, 3) 30 s waves, and 4) wake front perturbation < 0.01 Hz. The electromagnetic noise is caused by currents or drift driven instabilities in the dayside and wake boundary. 1 Hz whistlers also originate from the instabilities but propagate and group-standing in the Moon frame. 30 s waves of terrestrial ion foreshock are frequently observed around the Moon even 60 RE upstream from the Earth when the interplanetary magnetic field (IMF) connects to the bow shock. 30 s waves are also occasionally generated by the ions reflected from the Moon when IMF is parallel to the solar wind. The wake front perturbation is observed with right-hand and left-hand polarizations at inbound and outbound the wake, respectively. These features suggest that they are phase-standing whistler perturbation outward the wake edge Doppler-shifted by the spacecraft velocity.