INVESTIGADORES
BERTUCCI Cesar
congresos y reuniones científicas
Título:
Magnetic Field Draping Enhancement at Weakly Magnetized Bodies
Autor/es:
BERTUCCI, C.; MAZELLE, C.; CRIDER, D.; ACUNA, M.; CONNERNEY, J.; MITCHELL, D.; LIN, R.; REME, H.; NESS, N.; WINTERHALTER, D.
Reunión:
Congreso; AGU Fall Meeting 2002; 2002
Resumen:
The lack of an intrinsic magnetic field at Venus, Mars and comets makes
their interaction with the solar wind to exhibit many similarities.
Among these, the formation of a magnetic barrier in front of a highly
conducting obstacle and an induced magnetic tail are the most
characteristic peculiarities. At Mars and comets, a sharp plasma
boundary that represents the outer edge of the magnetic barrier, the
Magnetic Pileup Boundary (MPB), has been identified by very clear
observational signatures, including a gradient in the magnetic field
magnitude (frequently observed as a sharp jump) accompanied by a
decrease in the magnetic field fluctuations, and a simultaneous drastic
decrease in the solar wind electron and proton densities, as the
exospheric-induced ions become more important. Recently, an analysis of
the 3-D magnetic field topology in the surroundings of the Martian MPB
using Mars Global Surveyor magnetometer data has revealed a sudden
enhancement of the field line draping exactly at the boundary itself.
This feature appears to be a ubiquitous characteristic of this boundary,
even when there is no obvious signature on the magnetic field magnitude.
We apply the same technique to magnetometer data acquired near comets
and Venus to show that this enhancement of draping is a commonplace for
all weakly magnetized atmospheric bodies. As a corollary, we propose for
the first time a mean to find the location of the counterpart of the MPB
at Venus. Despite numerous studies on the physics of the Venusian
magnetic barrier, such boundary has never been reported since there is
usually no clear signature on the magnetic field magnitude.