HR: 17:15h
AN: SM14A-06 [Abstracts]
TI: Field-line mapping of the near-Earth plasma sheet based on the plasma pressure information obtained by
GEOTAIL
AU: * Maezawa, K
EM: maezawa@stp.isas.jaxa.jp
AF: Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, 229-8510
Japan
AU: Mukai, T
EM: mukai@stp.isas.jaxa.jp
AF: Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, 229-8510
Japan
AU: Saito, Y
EM: saito@stp.iasa.jaxa.jp
AF: Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, 229-8510
Japan
AB:
The magnetic field line mapping of the magnetotail is a very important issue since physical interpretaion of any correlatinal
studies between ionospheric phenomena (e.g. auroral break up) and magnetospheric phenomena (e.g. fast plasma flows) is
directly affected by the field-line mapping. We here present a unique method to trace field lines from plasma measurements
in the magnetotail.
The plasma pressure balance equation tells us that the plasma pressure should be constant along the field lines since the JxB
force counterbalancing the pressure gradient is perpendicular to the magnetic field. Therefore the contour lines of
constant plasma pressure in the x-z plane of the magnetotail represent the magentic field lines themselves. Based on this
idea, we have analyzed the average plasma pressure distribution in the magnetotail using 10 years data from GEOTAIL, for
various conditions of solar wind/IMF parameters including IMF Bz polarity. The result indicates a quantitative difference in
the latitude-eauatorial distance relationship, i.e., in the degree of stretching of field lines for different polarities of
IMF. We emphasize that this is the first time that the large-scale configuration of magnetic field lines is deduced without
introducing any model parameters. Our method is also unique in that it is based on plasma data only. We will comment on the
consistency/inconsistency of our result with the Tyganenko field models.
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2736 Magnetosphere/ionosphere interactions
DE: 2740 Magnetospheric configuration and dynamics
DE: 2744 Magnetotail
DE: 2764 Plasma sheet
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting