RESPONSE OF MAGNETIC INDICES TO DIFFERENT SOLAR WIND DISTURBANCES

摘要

We have investigated the magnetic storms during the rising phase of the solar cycle 23 from January 1996 to December 1999. We determined the storm periods from both the Dst and Kp indices. Study was limited to storms with Dst ≤ ―50 nT or Kp ≥ 5. We have investigated cross-correlation between the peak Dst and Kp values of storms organized according to the associated solar wind driver. It makes a difference whether the Earth's magnetosphere is hit by a CME ejecta or by a compressed and heated sheath region plasma. We found different behavior of the Kp and Dst indices during different types of solar wind drivers. Intense and short-time disturbances, like post-shock streams and sheath regions geliera-ted more Kp storms and ejecta generated more Dst storms. Thus one should be careful when comparing studies based on any single activity index.