IMF B/sub y/ dependence of region 1 Birkeland currents near noon
We have conducted a statistical study of large-scale Birkeland currents, hot plasma, and the B/sub y/ component of the interplanetary magnetic field. Forty-eight Viking orbits from July 19, 1986, to September 2, 1986, were used in the study during a time period when the 3-R/sub E/ geocentric apogee was located near the dayside high-latitude region usually associated with the polar cusp. We first compared the location of magnetosheathlike electrons to the region 1 and ''traditional cusp'' Birkeland current systems near noon. It was found that the region 1 Birkeland current system was colocated with the region of most intense magnetosheathlike electron flux. We therefore infer that the ''tradional cusp'' current system, located poleward of the region 1 system, is associated with field lines that extend to the plasma mantle in the outer magnetosphere. Using this same data base a statistical study between the B/sub y/ component of the IMF and the flow direction of the region 1 Birkeland current system as a function of magnetic local time was performed. We determined that the flow direction of the region 1 current system near noon depends on the B/sub y/ component of IMF. The meridian that separates the dawnside and duskside region 1 Birkeland currents shifted to magnetic local times before noon when B/sub y/ was less than 0 nT, and to the afternoon when B/sub y/ was greater than 0 nT. The extent of the shift away from noon was dependent on the magnitude of the IMF B/sub y/ component. copyright American Geophysical Union 1988
- Research Organization:
- The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland
- OSTI ID:
- 6832346
- Journal Information:
- J. Geophys. Res.; (United States), Vol. 93:A9
- Country of Publication:
- United States
- Language:
- English
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