Anticipated electrical environment within permanently shadowed lunar craters

被引:73
作者
Farrell, W. M. [1 ,2 ]
Stubbs, T. J. [1 ,2 ,3 ]
Halekas, J. S. [2 ,4 ]
Killen, R. M. [1 ,2 ]
Delory, G. T. [2 ,4 ]
Collier, M. R. [1 ,2 ]
Vondrak, R. R. [1 ,2 ]
机构
[1] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20770 USA
[2] NASA, Ames Res Ctr, NASA Lunar Sci Inst, Moffett Field, CA 94035 USA
[3] Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA
[4] Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA
关键词
IN-CELL SIMULATIONS; PLASMA; WAKE; EXPANSION; POLES; SURFACE; VACUUM; WATER; ICE;
D O I
10.1029/2009JE003464
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
Shadowed locations near the lunar poles are almost certainly electrically complex regions. At these locations near the terminator, the local solar wind flows nearly tangential to the surface and interacts with large-scale topographic features such as mountains and deep large craters. In this work, we study the solar wind orographic effects from topographic obstructions along a rough lunar surface. On the leeward side of large obstructions, plasma voids are formed in the solar wind because of the absorption of plasma on the upstream surface of these obstacles. Solar wind plasma expands into such voids, producing an ambipolar potential that diverts ion flow into the void region. A surface potential is established on these leeward surfaces in order to balance the currents from the expansion-limited electron and ion populations. We find that there are regions near the leeward wall of the craters and leeward mountain faces where solar wind ions cannot access the surface, leaving an electron-rich plasma previously identified as an "electron cloud." In this case, some new current is required to complete the closure for current balance at the surface, and we propose herein that lofted negatively charged dust is one possible (nonunique) compensating current source. Given models for both ambipolar and surface plasma processes, we consider the electrical environment around the large topographic features of the south pole (including Shoemaker crater and the highly varied terrain near Nobile crater), as derived from Goldstone radar data. We also apply our model to moving and stationary objects of differing compositions located on the surface and consider the impact of the deflected ion flow on possible hydrogen resources within the craters.
引用
收藏
页数:14
相关论文
共 27 条
[1]  
[Anonymous], 1990, Energetic Charged-Particle Interactions with Atmospheres and Surfaces
[2]  
Berg O., 1976, Lunar soil movement registerd by the apollo 17 cosmic dust experiment, P233, DOI 10.1007/3-540-07615-8486
[3]  
Berg O. E., 1979, Space Science Instrumentation, V4, P329
[4]   Detailed structure and dynamics in particle-in-cell simulations of the lunar wake [J].
Birch, PC ;
Chapman, SC .
PHYSICS OF PLASMAS, 2001, 8 (10) :4551-4559
[5]   Particle-in-cell simulations of the lunar wake with high phase space resolution [J].
Birch, PC ;
Chapman, SC .
GEOPHYSICAL RESEARCH LETTERS, 2001, 28 (02) :219-222
[6]  
Carrier I.I.I.W.D., 1991, Lunar Sourcebook, a User's Guide to the Moon, P475
[7]   Space weathering effects on lunar cold trap deposits [J].
Crider, DH ;
Vondrak, RR .
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, 2003, 108 (E7)
[8]   EXPANSION OF A PLASMA INTO A VACUUM [J].
CROW, JE ;
AUER, PL ;
ALLEN, JE .
JOURNAL OF PLASMA PHYSICS, 1975, 14 (AUG) :65-76
[9]   The generation of lightning in the solar nebula [J].
Desch, SJ ;
Cuzzi, JN .
ICARUS, 2000, 143 (01) :87-105
[10]   Complex electric fields near the lunar terminator: The near-surface wake and accelerated dust [J].
Farrell, W. M. ;
Stubbs, T. J. ;
Vondrak, R. R. ;
Delory, G. T. ;
Halekas, J. S. .
GEOPHYSICAL RESEARCH LETTERS, 2007, 34 (14)