Recovery phase of magnetic storms induced by different interplanetary drivers

TL;DR

This study analyzes the recovery phase of magnetic storms caused by different interplanetary drivers, revealing distinct durations and behaviors, with strong storms fitting hyperbolic recovery models and moderate storms showing variable recovery times.

Contribution

It provides a comparative statistical analysis of storm recovery phases based on interplanetary driver types, highlighting differences in duration and recovery profiles.

Findings

Strong storms follow hyperbolic recovery with constant times.

Moderate storms exhibit increasing hyperbolic times during recovery.

Recovery durations vary with interplanetary driver type.

Abstract

Statistical analysis of Dst behaviour 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 $Dst(t)= a/(1+t/\tau_h)$ with constant $\tau_h$ times for all types of drivers while for moderate ($-100 < Dst_{min} < -50$ nT) storms $Dst$ profile can not be approximated by hyperbolic function with constant $\tau_h$ because hyperbolic time $\tau_h$ increases with increasing time of recovery phase. Relation between duration and value $Dst_{min}$ for storms induced by ICME and Sheath has 2 parts: $Dst_{min}$ and duration correlate at small durations while they anticorrelate at large durations.