Title: A coherent model of the crustal magnetic field of Mars

Author(s): Arkani-Hamed J

Source: JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS 109 (E9): Art. No. E09005 SEP 15 2004

Document Type: Article

Language: English

Abstract: The immense amount of the mapping-phase Mars Global Surveyor (MGS) magnetic data allows us to derive a highly accurate magnetic map of Mars. The data acquired at nighttimes within the first similar to3 years of the mapping phase are divided into two almost equal parts, and each part is expressed in spherical harmonics of degree up to 90. The two models are almost identical over harmonics of degree up to 62 but show appreciable differences over higher-degree harmonics, indicating that the higher-degree harmonic coefficients have appreciable noncrustal contribution. The most repeatable components of the two models are combined to produce an accurate 62-degree harmonic model of the magnetic field of the Martian crust. It is further demonstrated that the altitude of MGS is the major limiting factor of the resolution of the mapping-phase data. The small-scale features of the data, with wavelengths shorter than similar to400 km, have significant contribution from noncrustal sources. They are not useful for delineating the details of the magnetic source bodies in the crust.

Author Keywords: magnetic field of Mars; magnetic anomaly resolution; spherical harmonic model of the magnetic field of Mars; Mars; terrestrial planets

KeyWords Plus: SPHERICAL HARMONIC MODEL; SOLAR-WIND; ALTITUDE

Addresses: Arkani-Hamed J (reprint author), McGill Univ, 3450 Univ St, Montreal, PQ H3A 2A7 Canada
McGill Univ, Montreal, PQ H3A 2A7 Canada

E-mail Addresses: jafar@eps.mcgill.ca

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

IDS Number: 857NQ