1988 Fiscal Year Final Research Report Summary
PHYSICS OF MAGNETOSPHERIC POLAR CAP BY ANALYSIS OF FIELD-ALIGNED CURRENTS.
| Project/Area Number |
61540305
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Space and upper atmospheric physics
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| Research Institution | University of Tokyo |
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Principal Investigator |
IIJIMA Takesi Faculty of Science, University of Tokyo, 理学部, 助教授 (70011624)
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| Project Period (FY) |
1986 – 1988
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| Keywords | Westward ring current / Horizontal radial current / Dipolarization / Region 1 field-aligned current / region2沿磁力線電力系 / サブストーム / プラズマ応力 / プラズマ分布 / 北向き惑星間空間磁場 |
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| Research Abstract |
I have obtained new knowledge on magnetospheric physics, by analyzing the geomagnetic field data that was acquired with various artificial satellites, which includes the following:
1. Large-scale field-aligned current systems associated with northward interplanetary magnetic field (NBZ current system).
The NBZ field-aligned currents are thought to flow so as to transfer the sunward plasma stress down to the polar cap ionosphere so that large-scale sunward plasma convection is maintained in the central polar-cap plasma domain. The acquisition of this sunward plasma stress from the interplanetary medium is thought to take place in the magnetospheric high-latitude boundary layer often called the plasma mantle.
2. Large-scale Region 1 and Region 2 field-aligned current systems.
The region 1 current system is thought to originated in the magnetospheric voltage generator, whereas the region 2 current system is ascribable to the combination of the voltage generator and current generator.
3. Large-scale magnetospheric equatorial currents.
The electric current flowing parallel to and near the geomagnetic equatorial plane is comprised of an azimuthal current flowing westward and a radial current flowing toward the earth in the evening sector and away from the earth in the morning sector. These horizontal currents exhibit a net positive divergence (source) in the evening sector and a net negative divergence (sink) in the morning sector. The location, flow direction and the intensities of these divergent currents are almost identical with those of the region 2 field-aligned current system. The westward ring current and the region 2 current system are closely connected.
4. Substorm-associated field-aligned currents.
The three-dimensional current system throughout the course of substorm is not solely ascribable to a diversion of magnetospheric cross-tail current but a development of radial current is essental.
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Research Products
(10 results)
