Premium
Solar wind access to lunar polar craters: Feedback between surface charging and plasma expansion
Author(s) -
Zimmerman M. I.,
Farrell W. M.,
Stubbs T. J.,
Halekas J. S.,
Jackson T. L.
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl048880
Subject(s) - impact crater , ambipolar diffusion , solar wind , plasma , astrobiology , wake , physics , lunar craters , dusty plasma , atmospheric sciences , computational physics , environmental science , mechanics , quantum mechanics
Determining the plasma environment within permanently shadowed lunar craters is critical to understanding local processes such as surface charging, electrostatic dust transport, volatile sequestration, and space weathering. In order to investigate the nature of this plasma environment, the first two‐dimensional kinetic simulations of solar wind expansion into a lunar crater with a self‐consistent plasma‐surface interaction have been undertaken. The present results reveal how the plasma expansion into a crater couples with the electrically‐charged lunar surface to produce a quasi‐steady wake structure. In particular, there is a negative feedback between surface charging and ambipolar wake potential that allows an equilibrium to be achieved, with secondary electron emission strongly moderating the process. A range of secondary electron yields is explored, and two distinct limits are highlighted in which either surface charging or ambipolar expansion is responsible for determining the overall wake structure.