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A reexamination of pitch angle diffusion of electrons at the boundary of the lunar wake


Velocity distribution of the solar wind electrons injected into the lunar wake boundary is re-examined by using a simple model structure of inward electric field. The electrons that were flowing along the magnetic field lines undergo pitch angle scattering due to the electric field component perpendicular to the magnetic field. The electrons obtain perpendicular speeds twice as much as the drift speed. On the basis of the GEOTAIL observations of the whistler mode waves and strahl electrons, the intensity of the electric field and the thickness of the wake structure are estimated to be 28-40 mVm-1 and less than 20 km, respectively.


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Correspondence to Tomoko Nakagawa.

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Nakagawa, T., Iizima, M. A reexamination of pitch angle diffusion of electrons at the boundary of the lunar wake. Earth Planet Sp 58, e17–e20 (2006).

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Key words

  • Lunar wake
  • pitch angle diffusion
  • electric field
  • wake potential structure
  • electron distribution function