HR: 0800h
AN: SM51B-1306    [Abstracts]
TI: A New Method for Monitoring Dayside Ionospheric Convection
AU: * Lyatsky, W
EM: lyatsky@cspar.uah.edu
AF: Alabama A&M University, 4900 Meridian St, Normal, AL 35762 United States
AU: Tan, A
EM: arjun.tan@email.aamu.edu
AF: Alabama A&M University, 4900 Meridian St, Normal, AL 35762 United States
AB: The results, presented in our previous abstract, show that the polar cap PC index does not measure properly the ionospheric convection due to a strong effect of substorm field-aligned currents on the magnetic field in the polar cap. However, since the magnetic effect of substorm current wedge is significantly reduced with distance from the current wedge, we may try to develop a method for more reliable monitoring of dayside ionospheric convection using magnetic field measurements far away from substorm current wedge in the vicinity of the near-noon polar cap boundary. To test this method, we investigated the eastward Y magnetic field component, related to ionospheric currents normal to the polar cap boundary, at the Cambridge Bay (CB) station located near the polar cap boundary (CGL ~77.5°). We calculated 15-min mean values for this Y component and investigated their correlation with the solar wind coupling function and substorm activity. Our analysis showed that the magnetic field Y component near noon at Cambridge Bay shows a good correlation with solar wind coupling function. This correlation is much better than the PC index shows. The correlation between the Y component and the coupling function remains good enough for all values of the AL index, which shows substorm activity. In contrast, the correlation between PC index and the coupling function drops significantly for low values of the AL index or when the values of AL index are restricted in a narrow interval. Variations of the eastward Y magnetic field component near the near-noon polar cap boundary are well correlated with solar wind coupling function in a wide enough sector of about 6 hours and may be used for reliable monitoring of dayside ionospheric convection, driven by solar wind electric field. In contrast to PC index, substorm current wedge does not affect significantly the magnetic field Y component in the vicinity of near-noon polar cap boundary.
DE: 2441 Ionospheric storms (7949)
DE: 2788 Magnetic storms and substorms (7954)
DE: 7894 Instruments and techniques
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005