Sun-Earth connection Event of Super Geomagnetic Storm on March 31, 2001: the Importance of Solar Wind Density

Abstract

An X1.7 flare at 10:15 UT and a halo CME with a projected speed of 942 km/s erupted from NOAA solar active region 9393 located at N20W19, were observed on 2001 March 29. When the CME reached the Earth, it triggered a super geomagnetic storm (hereafter super storm). We find that the CME always moved towards the Earth according to the intensity-time profiles of protons with different energies. The solar wind parameters responsible for the main phase of the super storm occurred on March 31, 2001 is analyzed taking into account the delayed geomagnetic effect of solar wind at the L1 point and using the SYM-H index. According to the variation properties of SYM-H index during the main phase of the super storm, the main phase of the super storm is divided into two parts. A comparative study of solar wind parameters responsible for the two parts shows the evidence that the solar wind density plays a significant role in transferring solar wind energy into the magnetosphere, besides the southward magnetic field and solar wind speed.

Cited by in corpus (5)

• The Sun and Space Weather
• Dependence of great geomagnetic storm intensity ($\Delta$SYM-H$\le$-200 nT) on associated solar wind parameters
• Dependence of Intensities of Major Geomagnetic Storms (Dst $\le$ -100 nT) on Associated Solar Wind Parameters
• Application of a magnetic-field-induced transition in Fe X to solar and stellar coronal magnetic field measurements
• Can we estimate the intensities of great geomagnetic storms($\Delta$SYM-H$\le -$200 nT) by Burton equation or by O'Brien and McPherron equation?