Figure 1

The harmonic waves detected by Kaguya on 13 June 2008. (a) The fast Fourier transform (FFT) spectrum of magnetic field. (b) The ellipticity spectrum. The angles (c) between the wave vector and the sunward direction (θ _kx ) and (d) between the wave vector and the magnetic field (θ _kB ). (e) The magnetic field vector components in the Selenocentric Solar Ecliptic (SSE) coordinates. Ellipticity is defined as (R − L)/(R + L), where R and L represent the right- and left-hand polarized components of the intensity of the waves, respectively. (f) The spacecraft trajectory during 00:00 to 01:00 UT (green line) and magnetic field vectors (magenta arrows) with respect to the Moon. The black contour indicates 0.5-nT magnetic field strength at an altitude of 100 km (Tsunakawa et al. 2010). The yellow and gray hemispheres in (f) represent the dayside and nightside of the Moon, respectively. The orange arrow represents the sunward direction from the subsolar point. The thick red line superposed on the trajectory represents the period during 00:05 to 00:40 UT indicated by a red bar just below (a). (g) The total, R, L, and compressional (C) components of the wave intensity versus the frequency at 00:29 UT. (h) The waveform of the two transverse (T1, T2) and C components with respect to the mean field during 00:28:40 to 00:29:00 UT.