TY - GEN

T1 - Recent progress in the data-based modeling of magnetospheric currents

AU - Tsyganenko, NA

PY - 2000

Y1 - 2000

N2 - Magnetospheric currents are very diverse and dynamical. The magnetopause shrinks, expands, and erodes, with varying degree of connection to the IMF. Intrusion of the plasma in the polar cusps results in diamagnetic currents which depress the field at high latitudes. The tail current sheet warps, bends, and twists, and its current density varies as the tail stretches and rebounds. Birkeland currents vary with the IMF and with the substorm cycle, and the ring current builds up and decays in the course of storms. During substorms, a dynamical current wedge develops on the nightside, resulting in a rapid reconfiguration of the near-Earth field. The data-based approach to magnetospheric modeling is to develop a flexible representation for the magnetic field vector and fit it to a large set of spacecraft data. All the above currents should be represented in the models in a meaningful way, and substantial advance was made recently in this direction. The new models feature a continuous parametric dependence on the solar wind conditions, include Birkeland currents, and have a solar-wind controlled magnetopause with a penetration of the IMF. New techniques are now available for modeling the twisting and warping of the cross-tail current, the collapse of the tail field during substorms, and the observed structure of the polar cusps. This article overviews some of those developments.

AB - Magnetospheric currents are very diverse and dynamical. The magnetopause shrinks, expands, and erodes, with varying degree of connection to the IMF. Intrusion of the plasma in the polar cusps results in diamagnetic currents which depress the field at high latitudes. The tail current sheet warps, bends, and twists, and its current density varies as the tail stretches and rebounds. Birkeland currents vary with the IMF and with the substorm cycle, and the ring current builds up and decays in the course of storms. During substorms, a dynamical current wedge develops on the nightside, resulting in a rapid reconfiguration of the near-Earth field. The data-based approach to magnetospheric modeling is to develop a flexible representation for the magnetic field vector and fit it to a large set of spacecraft data. All the above currents should be represented in the models in a meaningful way, and substantial advance was made recently in this direction. The new models feature a continuous parametric dependence on the solar wind conditions, include Birkeland currents, and have a solar-wind controlled magnetopause with a penetration of the IMF. New techniques are now available for modeling the twisting and warping of the cross-tail current, the collapse of the tail field during substorms, and the observed structure of the polar cusps. This article overviews some of those developments.

KW - NEAR-EARTH MAGNETOTAIL

KW - SOLAR-WIND CONTROL

KW - MAGNETIC-FIELD

KW - QUANTITATIVE MODELS

KW - MAGNETOPAUSE SHAPE

KW - GEOMAGNETIC-FIELD

KW - PRESSURE BALANCE

KW - CURRENT SHEET

KW - SIZE

KW - PARAMETERS

M3 - Conference contribution

SN - 0-87590-976-0

VL - 118

T3 - GEOPHYSICAL MONOGRAPH SERIES

SP - 61

EP - 70

BT - MAGNETOSPHERIC CURRENT SYSTEMS

A2 - Ohtani, S

A2 - Fujii, R

A2 - Hesse, M

A2 - Lysak, RL

PB - American Geophysical Union

T2 - Conference on Magnetospheric Current Systems

Y2 - 10 January 1999 through 15 January 1999

ER -