Recovery phase of magnetic storms induced by different interplanetary drivers

Statistical analysis of Dst behavior during recovery phase of magnetic storms induced by different types of interplanetary drivers is made on the basis of OMNI data in period 1976–2000. We study storms induced by ICMEs (including magnetic clouds (MC) and Ejecta) and both types of compressed regions: corotating interaction regions (CIR) and Sheaths. The shortest, moderate and longest durations of recovery phase are observed in ICME‐, CIR‐ , and Sheath‐induced storms, respectively. Recovery phases of strong ( Dst min ≤ −100 nT) magnetic storms are well approximated by hyperbolic functions Dst ( t ) = a /(1 + t / τ h ) with constant τ h times for each types of drivers while for moderate (−100 < Dst min ≤ −50 nT) storms Dst profile can not be approximated by hyperbolic function with constant τ h times because hyperbolic τ h times increase with increasing time of recovery phase. Dependence of τ h times on types of interplanetary drivers is the same as indicated above. Relation between duration and value Dst min for storms induced by MC and Sheath has 2 parts: module of Dst min and duration correlate at small durations while they anticorrelate at large durations. Obtained results show that recovery phase Dst variations depend on type of interplanetary drivers inducing magnetic storms.