Paraboloid model of Mercury's magnetosphere

Abstract

A new “Paraboloidal” model of Mercury's magnetospheric magnetic field based upon the earlier terrestrial model and using similar techniques is developed. The model describes the field of Mercury's dipole, which is considered to be offset from the planet's center; the magnetopause currents driven by the solar wind; and the tail current system including the cross‐tail currents and their closure currents at the magnetopause. The effect of the interplanetary magnetic field (IMF) is modeled as a partial penetration of the IMF into the magnetosphere. The goals of the present work are (1) to develop an easily usable, yet robust model of Mercury's magnetospheric magnetic field and (2) to produce an improved “unified” determination of Mercury's magnetic dipole moment which fits the measurements taken during both Mariner 10's first and third flybys. This new model of Mercury's magnetosphere is described and used to determine a best Mercury magnetic dipole moment of 192 nT RM3, from the two Mariner 10 flybys, a value which is intermediate between the various estimates produced by previous models. The best fit to the Mariner 10 measurements gives the dipole offset 0.18 RM above the equatorial plane. The new Paraboloidal model is used to predict the configuration of this miniature magnetosphere under average and extreme solar wind conditions.