Whistler waves observed near lunar crustal magnetic sources

We present Lunar Prospector Magnetometer (LP MAG) observations of monochromatic circularly polarized low frequency waves at frequencies of 0.4–4 Hz near the Moon. We observe such waves on about 6.6% of LP orbits in the solar wind, outside of the lunar wake. About a third of them occur on orbits when we also observe external magnetic enhancements (“limb shocks”), and most are clearly associated with lunar crustal magnetic sources, indicating an origin related to solar wind interaction with lunar magnetic fields. The inferred propagation vectors and polarizations of these waves are consistent with the expected characteristics of whistler‐mode waves. These observations could indicate either upstream whistler waves produced at shock surfaces above lunar crustal magnetic sources, or phase‐standing whistler wakes formed by direct solar wind interaction with lunar crustal magnetic fields.

[1]  D. Mitchell,et al.  On the occurrence of magnetic enhancements caused by solar wind interaction with lunar crustal fields , 2006 .

[2]  D. Mitchell,et al.  Electrons and magnetic fields in the lunar plasma wake , 2005 .

[3]  T. Nakagawa,et al.  GEOTAIL observation of upstream ULF waves associated with lunar wake , 2003 .

[4]  D. Mitchell,et al.  Observations of low‐frequency electromagnetic plasma waves upstream from the Martian shock , 2002 .

[5]  Mario H. Acuna,et al.  Hybrid simulations of solar wind interaction with magnetized asteroids: General characteristics of the interaction region , 2001 .

[6]  Christopher T. Russell,et al.  Time series data analyses in space physics , 1999 .

[7]  Hood,et al.  Lunar surface magnetic fields and their interaction with the solar wind: results from lunar prospector , 1998, Science.

[8]  M. Kivelson,et al.  Asteroid interaction with solar wind , 1996 .

[9]  C. Owen,et al.  Upstream ULF waves and energetic electrons associated with the lunar wake: Detection of precursor activity , 1996 .

[10]  D. Gurnett Comment on "The whistler-mode bow wave of an asteroid , 1995 .

[11]  Krishan K. Khurana,et al.  Solar wind interaction with small bodies: 1. Whistler wing signatures near Galileo's closest approach to Gaspra and Ida , 1995 .

[12]  D. Orlowski,et al.  Upstream waves at mercury, Venus and earth: Comparison of the properties of one Hertz waves , 1990 .

[13]  D. Fairfield Whistler waves observed upstream from collisionless shocks , 1974 .

[14]  L. J. Cahill,et al.  Magnetopause structure and attitude from Explorer 12 observations. , 1967 .