HR: 1340h
AN: SM23A-1189    [Abstracts]
TI: Study of the Effects of Auroral Substorms on the Low-Latitude Currents
AU: * Maslova, I
EM: inga@cc.usu.edu
AF: Utah State University, Mathematics and Statistics Department 3900 Old Main Hill, Logan, UT 84322-3900, United States
AU: Kokoszka, P
EM: piotr@cc.usu.edu
AF: Utah State University, Mathematics and Statistics Department 3900 Old Main Hill, Logan, UT 84322-3900, United States
AU: Sojka, J J
EM: sojka@cc.usu.edu
AF: Utah State University, Center for Atmospheric and Space Sciences 4405 Old Main Hill, Logan, UT 84322-4405, United States
AU: Zhu, L
EM: zhu@cc.usu.edu
AF: Utah State University, Center for Atmospheric and Space Sciences 4405 Old Main Hill, Logan, UT 84322-4405, United States
AB: In recent years there has been some discussions on whether or not the auroral substorms have an effect on the equatorial and mid-latitude currents. Our work was motivated by this problem. We use a novel statistical technique that allows us to test at a specified significance level whether such an effect exists. Our approach uses the original 1-min data of H component measurements, rather than the derived indices as in some previous related studies. One of the shortcomings of the correlation analysis based on indices like AE, Kp or Dst is that the physical interpretation of the indices is not always obvious. Furthermore, interpretation of a correlation analysis of such derived data is not straightforward, as statistical uncertainty cannot be readily quantified. The approach we propose here is novel in several ways: 1) we work directly with the measurements of the magnetic field, rather than indices; 2) we view magnetometer records over one day as single functional observations; 3) we use a statistical test of significance, which by its very nature takes into account random variability not attributable to physical effects. We show that the substorms do affect low-latitude currents at all longitudes. It appears that this dependence is significant not only during the same day the substorm occurs, but also the next day. Our study shows that the effect normally fades out two days after the substorms. It decreases in time faster for the cases of weak and medium substorms than those of strong substorms.
DE: 2409 Current systems (2721)
DE: 2415 Equatorial ionosphere
DE: 2790 Substorms
DE: 2794 Instruments and techniques
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting