Modeling the recovery phase of extreme geomagnetic storms

TL;DR

This paper validates a hyperbolic decay model for the recovery phase of extreme geomagnetic storms, showing it accurately reproduces the decay and reveals an exponential relationship between storm severity and recovery time.

Contribution

It demonstrates the hyperbolic model's effectiveness for severe storms and uncovers a linear relationship between storm severity and recovery time in less intense cases.

Findings

Hyperbolic decay function accurately models extreme storm recovery

Recovery time depends exponentially on storm intensity

Linear approximation valid for less severe storms

Abstract

The recovery phase of the largest storms ever recorded has been studied. These events provide an extraordinary opportunity for two goals: (1) to validate the hyperbolic model by Aguado et al. [2010] for the recovery phase after disturbances as severe as the Carrington event, or that related to the Hydro-Quebec blackout in March 1989, and (2) to check whether the linear relationship between the recovery time and the intensity of the storm still complies. Our results reveal the high accuracy of the hyperbolic decay function to reproduce the recovery phase of the magnetosphere after an extreme storm. Moreover, the characteristic time that takes the magnetosphere to recover depends in an exponential way on the intensity of the storm, as indicated by the relationship between the two parameters involved in the hyperbolic decay. This exponential function can be approached by a linear function when the severity of the storm diminishes.