Dusty plasmas at the Moon: Effects of magnetic fields

Abstract

Processes associated with the presence of magnetic fields, which can be important in dusty plasmas on the Moon, are considered. Lower-hybrid wave processes under interaction of the magnetotail of the Earth with dusty plasma near the surface of the Moon are described. Lower-hybrid waves are excited due to the relative motion of magnetospheric ions and charged dust grains, which leads to the establishment of a well developed lower hybrid plasma turbulence. The effective collision frequency characterizing the anomalous loss of ion momentum due to ion-wave interaction, as well as the electric fields arising in the system are found. It is shown that the electric fields excited due to the development of lower-hybrid turbulence are somewhat weaker than those arising due to the charging of the lunar surface under the action of solar radiation. Nevertheless, they are quite significant to affect the electric field pattern above the Moon. The obtained effective collision frequencies should be taken into account when deriving hydrodynamic equations for dusty plasma ions with allowance for their turbulent heating. Problems related to the consideration of magnetic fields, which can be important for detailed study of the dusty plasmas at the Moon, are stated. The possibility of generation of wave motions in the near-surface lunar plasma should be taken into consideration when interpreting the observational data.