Influence of the interplanetary driver type on the durations of main and recovery phases of magnetic storms

We study durations of main and recovery phases of magnetic storms induced by different types of large-scale solar-wind streams (Sheath, magnetic cloud (MC), Ejecta and CIR) on the basis of OMNI data base during 1976-2000. Durations of both main and recovery phases depend on types of interplanetary drivers. On the average, duration of main phase of storms induced by compressed regions (CIR and Sheath) is shorter than by MC and Ejecta while duration of recovery phase of CIR- and Sheath-induced storms is longer. Analysis of durations of individual storms shows that durations of main and recovery phases anti-correlate for CIR- and Sheath-induced storms and there is not dependence between them for (MC+Ejecta)-induced storms.