Solar Wind Control of the Magnetospheric and Auroral Dynamics |
| |
Authors: | I I Alexeev |
| |
Institution: | (1) Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Leninskie Gory, Moscow, 119992, Russia |
| |
Abstract: | A dependence of the polar cap magnetic flux on the interplanetary magnetic field and on the solar wind dynamic pressure is
studied. The model calculations of the polar cap and auroral oval magnetic fluxes at the ionospheric level are presented.
The obtained functions are based on the paraboloid magnetospheric model calculations. The scaling law for the polar cap diameter
changing for different subsolar distances is demonstrated. Quiet conditions are used to compare theoretical results with the
UV images of the Earth’s polar region obtained onboard the Polar and IMAGE spacecrafts. The model calculations enable finding
not only the average polar cap magnetic flux but also the extreme values of the polar cap and auroral oval magnetic fluxes.
These values can be attained in the course of the severe magnetic storm. Spectacular aurora often can be seen at midlatitude
during severe magnetic storm. In particularly, the Bastille Day storm of July 15–16, 2000, was a severe magnetic storm when
auroral displays were reported at midlatitudes. Enhancement of global magnetospheric current systems (ring current and tail
current) and corresponding reconstruction of the magnetospheric structure is a reason for the equatorward displacement of
the auroral zone. But at the start of the studied event the contracted polar cap and auroral oval were observed. In this case,
the sudden solar wind pressure pulse was associated with a simultaneous northward IMF turning. Such IMF and solar wind pressure
behavior is a cause of the observed aurora dynamics. |
| |
Keywords: | magnetosphere magnetic storm aurora polar cap magnetospheric model |
本文献已被 SpringerLink 等数据库收录! |
|