Organization of the magnetosphere during substorms

TL;DR

This paper investigates how the Earth's magnetosphere reorganizes during substorms, showing it self-organizes globally without increased predictability, supported by analysis of 500 substorms and a minimal model.

Contribution

It provides evidence that the magnetosphere self-organizes during substorms and introduces a minimal dynamic-stochastic model reproducing substorm statistical features.

Findings

Magnetosphere self-organizes globally during substorms

No increase in predictability during substorms

A minimal model reproduces statistical features of substorm indices

Abstract

The change in degree of organization of the magnetosphere during substorms is investigated by analyzing various geomagnetic indices, as well as interplanetary magnetic field z-component and solar wind flow speed. We conclude that the magnetosphere self-organizes globally during substorms, but neither the magnetosphere nor the solar wind become more predictable in the course of a substorm. This conclusion is based on analysis of five hundred substorms in the period from 2000 to 2002. A minimal dynamic-stochastic model of the driven magnetosphere that reproduces many statistical features of substorm indices is discussed.