Comment on “Properties of the recovery phase of extreme storms” by
Choraghe et al. (2021)
Abstract
Choraghe et al. (2021), based on a study of the recovery phase of the
SYM-H index of 31 extreme geomagnetic storms, have recently concluded
that the hyperbolic decay function is only able to explain the complete
recovery phase of about one third of events and that both the
exponential or the hyperbolic decay functions fail to explain the late
recovery phase of storms. Furthermore, they propose a linear function to
model the late recovery phase and claim that the proposed model could
throw new light on the relative importance of different physical
processes involved during the complete recovery phase of extreme storms.
We assert that \citeA{Choraghe} conclusions regarding
the recovery phase of extreme storms analysis are incorrect and in
particular are based on a misunderstanding of the nature of the
evolution of the SYM-H index and the energy balance of the ring current.