MESSENGER observations of Mercury's magnetic field structure
Name
Zuber_Messenger observations.pdf
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3.82 MB
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Adobe PDF
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Author(s)
Johnson, Catherine L.
Purucker, Michael E.
Korth, Haje
Anderson, Brian J.
Winslow, Reka M.
Al Asad, Manar M. H.
Slavin, James A.
Alexeev, Igor. I.
Phillips, Roger J.
Zuber, Maria
Date Issued
December 2012
Journal
Journal of Geophysical Research: Planets
Publisher
American Geophysical Union
Citation
Johnson, Catherine L., Michael E. Purucker, Haje Korth, Brian J. Anderson, Reka M. Winslow, Manar M. H. Al Asad, James A. Slavin, et al. “MESSENGER Observations of Mercury’s Magnetic Field Structure.” J. Geophys. Res. 117, no. E12 (December 2012): E00L14.
Version
Final published version
Abstract
We present a baseline, time-averaged model for Mercury's magnetosphere, derived from MESSENGER Magnetometer data from 24 March to 12 December 2011, comprising the spacecraft's first three Mercury years in orbit around the innermost planet. The model, constructed under the approximation that the magnetospheric shape can be represented as a paraboloid of revolution, includes two external (magnetopause and magnetotail) current systems and an internal (dipole) field and allows for reconnection. We take advantage of the geometry of the orbital Magnetometer data to estimate all but one of the model parameters, and their ranges, directly from the observations. These parameters are then used as a priori constraints in the paraboloid magnetospheric model, and the sole remaining parameter, the dipole moment, is estimated as 190 nTRM3from a grid search. We verify that the best fit dipole moment is insensitive to changes in the other parameters within their determined ranges. The model provides an excellent first-order fit to the MESSENGER observations, with a root-mean-square misfit of less than 20 nT globally. The results show that the magnetopause field strength ranges from 10% to 50% of the dipole field strength at observation locations on the dayside and at nightside latitudes north of 60°N. Globally, the residual signatures observed to date are dominated by the results of magnetospheric processes, confirming the dynamic nature of Mercury's magnetosphere.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1029/2012je004217
