The Electron Density Structure of Mars Magnetosphere by MAVEN/LPW

Tuesday, 15 December 2015
Poster Hall (Moscone South)
Michiko Morooka1, Laila Andersson2, Robert E Ergun3, Christopher M Fowler1, Gregory T Delory4, Tristan David Weber2, Adam K Woodson3, David J Andrews5, Anders I Eriksson5, David L Mitchell6, John E P Connerney7, Jacob Gruesbeck8, Jasper S Halekas9, Niklas J. T. Edberg5 and James P McFadden6, (1)Laboratory for Atmospheric and Space Physics, Boulder, CO, United States, (2)University of Colorado at Boulder, Boulder, CO, United States, (3)University of Colorado, Laboratory for Atmospheric and Space Research, Boulder, CO, United States, (4)University of California, Space Sciences Laboratory, Berkeley, CA, United States, (5)IRF Swedish Institute of Space Physics Uppsala, Uppsala, Sweden, (6)University of California Berkeley, Berkeley, CA, United States, (7)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (8)University of Maryland College Park, College Park, MD, United States, (9)University of Iowa, Iowa City, IA, United States
The Langmuir probe (LP) is primarily designed to characterize the plasma by direct analysis of the collected plasma particle current in a dense and cold plasma regime. On the other hand in the tenuous plasma the floating potential of the spacecraft is anti-correlated with the flux of the ambient electrons, and therefore provides a qualitative and sensitive indication of variations in the ambient plasma. The advantage of this measurement is that the obtained density yields the overall ambient plasma density irrespective of the particle energy range and sensitive to low-density plasma. Langmuir Probe sensors onboard two spacecraft (Phobos-2 and Rosetta) have identified the plasma regions around Mars magnetosphere using the LP measured spacecraft potentials. However, the examples of such observation are few. A set of Langmuir Probe onboard MAVEN makes possible to monitor the spacecraft potentials around Martian magnetosphere statistically. In most of the cases MAVEN/LPW identifies sharp density jumps near the location previously reported as the magnetic pile-up boundary. We will show the electron density characteristics and its comparison to the characteristics of thermal electron/ion as well as the magnetic field activities and discuss their relation to the Solar wind conditions and Martian magnetic field.