INVESTIGADORES
BERTUCCI Cesar
artículos
Título:
Structure and variability of the Martian magnetic pileup boundary and bow shock from MGS MAG/ER observations
Autor/es:
BERTUCCI, C., MAZELLE, C., ACUÑA, M.H.
Revista:
ADVANCES IN SPACE RESEARCH
Editorial:
Elsevier
Referencias:
Lugar: Amsterdam; Año: 2005 vol. 36 p. 2066 - 2076
ISSN:
0273-1177
Resumen:
During the first 1.5 years of an ongoing successful mission, the Mars
Global Surveyor Magnetometer and Electron Reflectometer (MAG/ER) has
provided unprecedented information on different boundaries and regions
of the Marssolar wind interaction. This article discusses the magnetic
structure and variability of two major plasma boundaries: the bow shock
and the magnetic pileup boundary (MPB). MAG/ER observations conclude
that the Martian bow shock is a fast bow shock, strongly affected by
kinetic effects. The Martian bow shock position is highly variable on
the daily basis, but it does not depend on the solar cycle phase. In
addition, the bow shock position shows a slight asymmetry related to
the convection electric field but no evidence for influence by crustal
fields has been found. The MPB is a permanent, well-defined plasma
boundary which is characterized by strong changes in the magnetic field
and drastic changes in the dominant ion population. Studies on the
magnetic structure of the MPB from MGS MAG/ER have led to the
conclusion that this boundary is a well-defined current sheet whose
normal vector agrees with the normal to the fit obtained from Mars
Global Surveyor crossings. Similar boundaries have been observed around
Venus and comets, suggesting that the MPB could be a common feature for
all atmospheric unmagnetized bodies. At Mars, the MPB position varies
on the daily basis and correlates with the bow shock position. On the
other hand, the MPB position does not seem to be influenced by the
solar cycle, although a small northsouth asymmetry in its position
suggests a weak influence by crustal magnetic fields.