Space Weather: Intensity and Asymmetry of the Storm-Time Ring Current: Quantification and Prediction

Johns Hopkins University, Baltimore MD

Investigators

Abstract

The development and decay of magnetic storms has traditionally been addressed in terms of the Dst magnetic index. Although the Dst index is traditionally thought of as a measure of the intensity of the ring current, electric currents on the magnetopause and in the Earth's magnetotail make significant contributions. Using the Dst index thus leads to inaccuracies in estimates of the intensity of the ring current as well as inaccuracies in the timing of the development and decay of the ring current. In addition, the Dst index does not provide any information about the local-time distribution of the ring current. This project will utilize data from the IMAGE/HENA instrument along with magnetometer data (1) to develop a new index that accurately reflects the intensity of the ring current, (2) to address the predictability of the new index by examining the characteristics of its response to solar wind conditions, (3) to quantify the asymmetry of the ring current by parameterizing the local-time distribution of the ring current, and (4) to examine the ring current in terms of the Asy-H and Sym-H indices and relate that to the development of magnetic substorms. The new index will provide a more useful measure of the dynamical features of the ring current and the progression of magnetic storms.