Investigating the Relationship Between Physical Properties and Spatial Irregularities at Coronal Hole Boundaries

TL;DR

This study analyzes the physical properties and irregularities of a large coronal hole boundary, revealing differences linked to magnetic field configurations and reconnection processes.

Contribution

It introduces a case study combining Differential Emission Measure and correlation dimension mapping to investigate coronal hole boundary properties.

Findings

Leading boundary has higher plasma temperature and smoother boundary line.

Leading boundary is associated with stronger, unipolar magnetic fields.

Differences are linked to local magnetic field configurations and reconnection.

Abstract

Coronal hole boundaries are the interfaces between closed and open magnetic field regions in the solar atmosphere. Many fundamental processes take place at these regions, including magnetic reconnection that is responsible for solar wind release and restructuring of the solar magnetic field. In this paper, we present a case study in which we investigate the physical properties of the boundary of a large low-latitude coronal hole. Differential Emission Measure analysis is used to derive the plasma properties of these regions. We also apply correlation dimension mapping analysis to measure the irregularities of the coronal hole boundary. We find that the leading boundary of this coronal hole has a slightly higher average plasma temperature, is associated with a stronger and more unipolar magnetic field, and has a smoother boundary line than the trailing counterpart. These differences are hypothesised to be direct consequences of the local magnetic field configurations of the coronal hole boundary: the leading boundary corresponds to large, well-organised coronal loops, and the trailing boundary corresponds to more dispersed, randomly orientated small magnetic bipoles. Hence, we suggest that the surrounding magnetic field structure and the nature of magnetic reconnection influence the properties of coronal hole boundaries.