Geoscience Reference
In-Depth Information
DIAGNOSING THE MERCURY PLASMA ENVIRONMENT
USING LOW-FREQUENCY ELECTRIC FIELD
MEASUREMENTS
L. G. BLOMBERG
∗
andJ.A.CUMNOCK
Alfven Laboratory, School of Electrical Engineering
Royal Institute of Technology, SE-100 44 Stockholm, Sweden
∗
lars.blomberg@ec.kth.se
The magnetosphere of Mercury is most intriguing because of its extreme nature,
with scale sizes vastly different from the corresponding terrestrial ones, and a
harsh environment at a comparatively small solar distance. The present brief
paper summarizes some scientific topics where electric field measurements at
low frequency will make a significant contribution to the understanding of the
Mercury plasma environment, and discusses possible diagnostics.
1. Introduction
Mercury's magnetosphere is quite different from that of the Earth making it
interesting to study in its own right, yet the two magnetospheres are similar
enough to allow comparative studies which are highly likely to provide new
knowledge and improved understanding of them both. The electric field
describes the plasma transport in a magnetosphere. The electric field also
plays an important role in the interaction of the solar wind with the plan-
etary magnetosphere and in the interaction of the magnetosphere with the
underlying ionosphere, in the case of Earth, or, most likely, the underlying
planetary surface or its immediate environment, in the case of Mercury.
Finally, it is an important parameter for the energy transport between the
different regions.
BepiColombo Mercury Magnetospheric Orbiter (MMO) will make the
first observations ever of the low-frequency electric field in the Mercury
environment. The spacecraft is equipped with two pairs of sensors for the
electric field, Wire Probe anTenna (WPT)
1
and Mercury Electric Field In-
Situ TOol (MEFISTO).
1
,
2
The two pairs are orthogonally mounted in the
spacecraft spin plane and will measure the electric field vector in the spin
plane over a wide frequency range.
∗
Corresponding author.
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