Grad-Shafranov reconstruction of magnetic clouds: overview and improvements

TL;DR

This paper reviews and improves the Grad-Shafranov reconstruction method for analyzing magnetic flux ropes, demonstrating its application to interplanetary coronal mass ejections observed by spacecraft, with discussions on its limitations.

Contribution

The paper introduces enhancements to the Grad-Shafranov reconstruction technique and applies it to real spacecraft data for better analysis of magnetic clouds.

Findings

Reasonable reconstruction results for observed magnetic clouds.

Method shows limitations that must be considered during interpretation.

Applicable to both ideal and complex magnetic cloud cases.

Abstract

The Grad-Shafranov reconstruction is a method of estimating the orientation (invariant axis) and cross-section of magnetic flux ropes using the data from a single spacecraft. It can be applied to various magnetic structures such as magnetic clouds (MCs) and flux ropes embedded into the magnetopause and in the solar wind. We develop a number of improvements of this technique and show some examples of the reconstruction procedure of interplanetary coronal mass ejections (ICMEs) observed at 1 AU by the STEREO, WIND and ACE spacecraft during the minimum following the solar cycle 23. The analysis is conducted not only for ideal localized ICME events but also for non-trivial cases of magnetic clouds in fast solar wind. The Grad-Shafranov reconstruction gives reasonable results for the sample events, although it possesses certain limitations, which need to be taken into account during the interpretation of the model results.