Modeling of the corrected D st * index temporal profile on the main phase of the magnetic storms generated by different types of solar wind

Abstract

A modeling of the corrected (taking into account the magnetopause currents [9]) Dst* index during the main phase of magnetic storms generated by four types of the solar wind (SW), namely MC (10 storms), CIR (28 storms), Sheath (21 storms), and Ejecta (31 storms), is performed similarly to our previous work on the simple Dst index [8]. The “Catalog of large-scale solar wind phenomena during 1976–2000” ([1], ftp://ftp.iki.rssi.ru/pub/omni/) prepared on the basis of the OMNI database, was used for the identification of SW types. The time behavior of Dst* is approximated by a linear dependence on the integral electric field (sumEy), dynamic pressure (Pd), and fluctuation level (sB) of the interplanetary magnetic field (IMF). Three types of Dst* modeling are performed: (1) by individual values of the approximation coefficients; (2) by approximation coefficients averaged over SW type, and (3) in the same way as in (2) but with allowance for the Dst*-index values preceding the beginning of the main phase of the magnetic storm. The results of modeling the corrected Dst* index are compared to modeling of the usual Dst index. In the conditions of a strong statistical scatter of the approximation coefficients, the use of Dst instead of Dst* insignificantly influences the accuracy of the modeling and correlation coefficient.