Geoscience Reference
In-Depth Information
inside (reflected back into) the Hermean magnetospheric cavity due to the
dense ambient solar wind (30-70 cm
−
3
). Further, the possible existence of
radiation belts around Mercury may be inferred from synchrotron radiation
emissions with a peak around a few MHz.
8
2.9.2.
Solar activity
By monitoring bursts of solar radio emissions that indicate the solar distur-
bance level, it is possible to investigate the whole chain of events from the
Sun to the processes directly responsible for magnetospheric storms and
substorms at Mercury. Specific activity on the Sun can then be related to
specific activity in the Hermean magnetosphere. The time delay is some-
what less than one day, for example, for a solar coronal mass ejection to
reach Mercury. It will be possible to compare space weather effects on Mer-
cury with those on Earth, both directly when Earth and Mercury are close
to each other in heliospheric longitude, and indirectly when they are sepa-
rated in longitude.
3. Summary
Mercury's plasma environment in general and its magnetosphere in particu-
lar are exciting targets for future exploration. Since Mariner 10 did not and
Messenger will not measure the low-frequency electric field, BepiColombo
provides the first opportunity to make direct measurements of the electric
fields around Mercury.
References
1. H. Matsumoto, J.-L. Bougeret, L. G. Blomberg, H. Kojima, S. Yagitani,
Y. Omura, M. Moncuquet, G. Chanteur, Y. Kasaba, J.-G. Trotignon,
Y. Kasahara and BepiColombo MMO PWI Team, Plasma/Radio wave obser-
vations at Mercury by the BepiColombo MMO spacecraft,
Advances in Geo-
sciences
2005, this issue.
2. L. G. Blomberg, H. Matsumoto, J.-L. Bougeret, H. Kojima, S. Yagitani,
J. A. Cumnock, A. I. Eriksson, G. T. Marklund, J.-E. Wahlund, L. Bylander,
L. Ahlen, J. A. Holtet, E. Kallio, Y. Kasaba, A. Matsuoka, M. Moncuquet,
K. Mursula, Y. Omura and J. G. Trotignon, MEFISTO — An electric field
instrument for BepiColombo/MMO,
Adv. Space Res.
, in press, 2005.
3. J. A. Cumnock and L. G. Blomberg, The Mercury environment: A literature
survey,
Royal Inst. Technol. Report TRITA-ALP-2003-02
, 2003.
