The impact of coronal hole characteristics and solar cycle activity in reconstructing coronal holes with EUHFORIA

E Asvestari,J Magdalenic,M Temmer,S G Heinemann,S Poedts,E Kilpua,J Pomoell

doi:10.1088/1742-6596/1548/1/012004

Abstract

Modelling with high accuracy the open magnetic field and the fast solar wind in the heliosphere is essential for space weather forecasting purposes. Primary sources of open magnetic field flux are Coronal Holes (CH), uni-polar regions that appear as dark patches in the solar corona when observed in X-ray and extreme-ultraviolet (EUV) images due to having significantly lower density and temperature to their surroundings. Therefore, when assessing how well the open magnetic field and the fast solar wind are modelled one can look at how well the model performs on one of its fundamental functions, that of reconstructing coronal hole areas. In this study we investigate how the CH morphology (i.e. latitudinal position of the centre of mass, area, intensity, elongation) and the solar variability, from high to low activity periods, can affect the results. We also investigated the possibility that the model is reconstructing CHs that are systematically shifted with respect to their observed position. The study is applied on 15 CHs exhibiting different latitudinal position and geometry. We compare the modelled CH areas with boundaries obtained by remote sensing EUV observations using the CATCH tool (Collection of Analysis Tools for Coronal Holes). We found no apparent effect of the CH characteristics on the modelling capabilities. In addition, solar cycle activity seems not to have any effect either. However, we emphasize that our sample is small and this outcome highlights the need for an extended research.

Highlights

Space weather can have a strong socioeconomic impact and accurate predictions of solar transient phenomena, such as Coronal Mass Ejections (CME) and solar energetic particles, that can impact Earth and human activity in space and on ground, have become essential
That was done by considering the total number of pixels of the EUHFORIA generated map which are enclosed by the Coronal Holes (CH) EUV boundaries, Ntep, and the number of enclosed pixels that are correctly modelled as open field ones, Nofp
In this study we focused on investigating whether CH characteristics, and the solar cycle variability can have an effect on the modelling capabilities of the adopted Wang - Sheeley - Arge (WSA) model by EUHFORIA when used for reconstructing CH areas

Summary

Introduction

Space weather can have a strong socioeconomic impact and accurate predictions of solar transient phenomena, such as Coronal Mass Ejections (CME) and solar energetic particles, that can impact Earth and human activity in space and on ground, have become essential. When assessing how well the open magnetic field and the fast solar wind are modelled one can look at how well the model performs on one of its fundamental functions, that of reconstructing coronal hole areas.

Results

Conclusion