Title: Electron oscillations in the induced martian magnetosphere

Author(s): Winningham JD, Frahm RA, Sharber JR, Coates AJ, Linder DR, Soobiah Y, Kallio E, Espley JR, Lundin R, Barabash S, Holmstrom M, Andersson H, Yamauchi M, Grigoriev A, Scherrer JR, Jeffers SJ, Kataria DO, Kozyra JU, Luhmann JG, Roelof EC, Williams DJ, Livi S, Curtis CC, Hsieh KC, Sandel BR, Koskinen H, Sales T, Riihela P, Schmidt W, Grande M, Carter M, Sauvaud JA, Fedorov A, Thocaven JJ, McKenna-Lawler S, Orsini S, Cerulli-Irelli R, Maggi M, Wurz P, Bochsler P, Krupp N, Woch J, Franz A, Asamura K, Dierker C

Source: ICARUS 182 (2): 360-370 JUN 2006

Document Type: Article

Language: English

Abstract: The Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) experiment flown on the Mars Express (MEX) spacecraft includes the Electron Spectrometer (ELS) as part of its complement. The ELS instrument measures the differential electron flux spectrum in a 128-level logarithmic energy sweep within a time period of 4 s. The orbital path of MEX traverses the martian sheath, cusps, and tail where ELS recorded periodic electron intensity oscillations. These oscillations comprised periodic variations of up to an order of magnitude (peak to valley) in energy flux, with the largest amplitudes in the tens to hundreds of eV range. The observed oscillations displayed periods ranging from minutes down to the instrument sweep resolution of 4 s. In the cases analyzed here, the frequency of the integrated electron energy flux typically peaked between 0.01 and 0.02 Hz. This frequency range is nearly the same as the typical O+ gyrofrequency in the magnetosheath, calculated using magnetometer data from Mars Global Surveyor. Due to the motion of the spacecraft, it is unclear if the wave structures observed were permanent standing waves or rather constituted waves propagating past the spacecraft. (c) 2005 Elsevier Inc. All fights reserved.

Author Keywords: Mars; magnetosphere

KeyWords Plus: WAVES; MARS

Addresses: Winningham JD (reprint author), SW Res Inst, PO Drawer 28510,6220 Culebra Rd, San Antonio, TX 78228 USA
SW Res Inst, San Antonio, TX 78228 USA
Univ Coll London, Mullard Space Sci Lab, Dorking, Surrey RH5 6NT England
Finnish Meteorol Inst, Helsinki, FIN-00101 Finland
Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA
Swedish Inst Space Phys, Kiruna, S-98128 Sweden
Univ Michigan, Space Phys Res Lab, Ann Arbor, MI 48109 USA
Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA
Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA
Univ Arizona, Tucson, AZ 85721 USA
Univ Helsinki, Dept Phys Sci, Helsinki, FIN-00014 Finland
Rutherford Appleton Lab, Didcot, Oxon OX11 0QX England
Ctr Etud Spatiale Rayonnements, Toulouse, F-31028 France
Natl Univ Ireland, Space Technol Ireland, Maynooth, Kildare Ireland
Ist Fis Spazio Interplanetario, Rome, I-00133 Italy
Univ Bern, Inst Phys, Bern, CH-3012 Switzerland
Max Planck Inst Aeron, Katlenburg Lindau, D-37191 Germany
Inst Space & Astronaut Sci, Sagamihara, Japan
Tech Univ Carolo Wilhelmina Braunschweig, Braunschweig, D-38106 Germany

E-mail Addresses: dwinningham@swri.org

Publisher: ACADEMIC PRESS INC ELSEVIER SCIENCE, 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA

Subject Category: ASTRONOMY & ASTROPHYSICS

IDS Number: 052JE