A new approach to detect the boundaries of interplanetary events

TL;DR

This paper introduces a semi-automatic method for detecting interplanetary coronal mass ejection boundaries using temperature ratios and plasma beta values, applied to Ulysses data from 2000-2002.

Contribution

The paper presents a novel algorithm for boundary detection of interplanetary events, specifically CMEs, using temperature minima and plasma beta, with application to Ulysses data.

Findings

Identified boundaries of 200+ ICMEs during 2000-2002.

Established relationships between plasma beta and speed at different boundaries.

Demonstrated the method's effectiveness on four detailed event analyses.

Abstract

We propose a new method to scan the data and then to infer the boundaries of the interplanetary coronal mass ejections, especially the interplanetary events observed by \emph{Ulysses}. The local minima of the temperatures ratio measured by the spacecraft are used to scan and compute the potential boundaries of the interplanetary events. The low plasma beta values are then invoked to detect at least four boundaries, two for the beginning and two for the end of an interplanetary coronal mass ejection (ICME). Intermediate boundaries can be identified, as indicated by other plasma and magnetic field signatures, and these ones mark substructures of a complex event. Using the algorithm described in this article, we have compiled a list of the ICME events registered by \emph{Ulysses} spacecraft during 2000-2002, with their boundaries. After a statistical analysis, four relationships of the plasma beta with the speed are then inferred for the computed ICMEs, for each of the four detected boundaries in our compiled list. In order to exemplify the method we analyse in detail four events. This method provides premises for an alternative way of semi-automatic detection of the interplanetary events' boundaries observed by \emph{Ulysses} spacecraft. We introduce here also a method for visualisation of the magnetic field components that allows detection of plasma insulations and boundaries detection for other satellites too.