Relationship of the ASY-H index with interplanetary medium parameters and auroral activity in magnetic storm main phases during CIR and ICME events

In this study, we examine the relationship of the ASY-H index characterizing the partial ring current intensity with interplanetary medium parameters and auroral activity during the main phase of magnetic storms, induced by the solar wind (SW) of different types. Over the period 1979-2017, 107 magnetic storms driven by CIR and ICME (MC + Ejecta) events have been selected. We consider magnetic storms with Dst min≤-50 nТ. The average ASY-H index ( ASY aver) during the magnetic storm main phase is shown to increase with increasing SW electric field and southward IMF B z regardless of SW type. There is no relationship between ASY aver and SW velocity. For the CIR and ICME events, the average AE ( АЕ aver) and K p ( K р aver) indices have been found to correlate with ASY aver. The highest correlation coefficient between АЕ aver and ASY aver ( r =0.74) is observed for the magnetic storms generated by CIR events. A closer relationship between K p aver and ASY aver ( r =0.64) is observed for the magnetic storms induced by ICME events. The ASY aver variations correlate with Dst min. The relationship between ASY aver and the rate of storm development is weak.