A theory of field-aligned current generation from the plasma sheet and the poleward expansion of aurora sub-storms

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1990

OSTI ID:5609327

Yamauchi, Masatoshi

Generation of field-aligned currents in the plasma sheet in terms of magnetosphere-ionosphere coupling was studied. The plasma sheet and the ionosphere were treated as two-dimensional layers by height integration. In the magnetosphere between them, the Alfven-wave transition time through this region is assumed to be zero. The ionospheric momentum is allowed to be transferred to the plasma sheet. Both linear analyses and numerical simulation are performed to study the field-aligned current generation. In the linear analysis, evolution from initial perturbations is studied. Zero-order configurations are steady state without field-aligned currents. The field-aligned currents are treated as a perturbed quantity and linearly related with the other perturbed quantities. One result for the linear waves is that the magnetohydrodynamics (MHD) fast mode and Alfven mode are coupled through the ionospheric Hall current. The Hall current causes the dawn-dusk asymmetry: a westward-travelling wave is amplified on the region 1 current system, while an eastward-travelling wave is amplified elsewhere. The expansion phase of the magnetospheric substorm after the onset is numerically simulated on the near-earth plasma sheet.

• Research Organization: Alaska Univ., Fairbanks, AK (United States)
• OSTI ID: 5609327
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALFVEN WAVES
AURORAE
COMPUTERIZED SIMULATION
COUPLING
CURRENTS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC CURRENTS
EXPANSION
HALL EFFECT
HYDROMAGNETIC WAVES
IONOSPHERE
IONOSPHERIC STORMS
MAGNETIC RECONNECTION
MAGNETIC STORMS
PLANETARY IONOSPHERES
PLASMA SHEET
SIMULATION