NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Collections About News Help Login
Back to Results
A Comparison of ARTEMIS Observations and Particle-in-cell Modeling of the Lunar Photoelectron Sheath in the Terrestrial MagnetotailAs an airless body in space with no global magnetic field, the Moon is exposed to both solar ultraviolet radiation and ambient plasmas. Photoemission from solar UV radiation and collection of ambient plasma are typically opposing charging currents and simple charging current balance predicts that the lunar dayside surface should charge positively; however, the two ARTEMIS probes have observed energydependent loss cones and high-energy, surface-originating electron beams above the dayside lunar surface for extended periods in the magnetosphere, which are indicative of negative surface potentials. In this paper, we compare observations by the ARTEMIS P1 spacecraft with a one dimensional particle-in-cell simulation and show that the energy-dependent loss cones and electron beams are due to the presence of stable, non-monotonic, negative potentials above the lunar surface. The simulations also show that while the magnitude of the non-monotonic potential is mainly driven by the incoming electron temperature, the incoming ion temperature can alter this magnitude, especially for periods in the plasma sheet when the ion temperature is more than twenty times the electron temperature. Finally, we note several other plasma phenomena associated with these non-monotonic potentials, such as broadband electrostatic noise and electron cyclotron harmonic emissions, and offer possible generation mechanisms for these phenomena.
Document ID
20140010170
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
doi:10.1029/2011GL050321
Authors
Poppe, A. R. (California Univ. Berkeley, CA, United States)
Halekas, J. S. (California Univ. Berkeley, CA, United States)
Delory, G. T. (California Univ. Berkeley, CA, United States)
Farrell, W. M. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Angelopoulos, V. (University of Southern California Los Angeles, CA, United States)
McFadden, J. P. (California Univ. Berkeley, CA, United States)
Bonnell, J. W. (California Univ. Berkeley, CA, United States)
Ergun, R. E. (Colorado Univ. Boulder, CO, United States)
Date Acquired
July 24, 2014
Publication Date
January 4, 2012
Publication Information
Publication: Geophysical Research Letters
Publisher: American Geophysical Union
Volume: 39
Issue: 1
Subject Category
Lunar And Planetary Science And Exploration
Report/Patent Number
GSFC-E-DAA-TN9069
Funding Number(s)
CONTRACT_GRANT: NNG08EK33C
CONTRACT_GRANT: NAS5-02099
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Lunar
Modeling
Artemis

Related Records

There are no records associated with this record.
No Preview Available