Title: External fields on the nightside of Mars at Mars Global Surveyor mapping altitudes

Author(s): Ferguson BB, Cain JC, Crider DH, Brain DA, Harnett EM

Source: GEOPHYSICAL RESEARCH LETTERS 32 (16): Art. No. L16105 AUG 26 2005

Document Type: Article

Language: English

Abstract: More than four years of data taken from Mars Global Surveyor during its Mapping Phase Orbits ( 360 - 420 km altitude) over low field regions were examined. The nightside magnetic field data were binned according to a proxy solar wind pressure calculated from the dayside measurements. When the crustal field contribution calculated from the internal field model (FSU90) is removed, the distribution of residuals is bi-valued in the sunward component. Pass-by-pass inspections of the data sometimes show a sudden reversal of field, which occur on successive passes. Analysis indicates that for these orbits MGS traverses a current sheet that separates the two lobes of Mars' magnetotail. These results indicate that on the nightside the major contributor to the external field is the draping of the Interplanetary Magnetic Field about the planet and that care must be taken when utilizing such data for modeling Mars' internal field.

KeyWords Plus: CRUSTAL MAGNETIC-FIELD; SOLAR-WIND; MAG/ER EXPERIMENT; BOUNDARY; VENUS

Addresses: Ferguson BB (reprint author), Florida State Univ, Inst Geophys Fluid Dynam, Tallahassee, FL 32306 USA
Florida State Univ, Inst Geophys Fluid Dynam, Tallahassee, FL 32306 USA
Florida State Univ, Sch Computat Sci, Tallahassee, FL 32306 USA
Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA
Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA
Univ Washington, Dept Earth & Space Sci, Seattle, WA 98195 USA

E-mail Addresses: bruce@geomag.gfdi.fsu.edu, cain@gfdi.fsu.edu, dcrider@lepvax.gsfc.nasa.gov, brain@ssl.berkeley.edu, eharnett@u.washington.edu

Publisher: AMER GEOPHYSICAL UNION, 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA

Subject Category: GEOSCIENCES, MULTIDISCIPLINARY

IDS Number: 960CX