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Related papers: Reconstructing coronal hole areas with EUHFORIA an…

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In this study, we focus on improving EUHFORIA (European Heliospheric Forecasting Information Asset), a recently developed 3D MHD space weather prediction tool. EUHFORIA consists of two parts, covering two spatial domains; the solar corona…

In order to address the growing need for more accurate space weather predictions, a new model named EUHFORIA (EUropean Heliospheric FORecasting Information Asset) was recently developed (Pomoell and Poedts, 2018). We present first results…

Global coronal models seek to produce an accurate physical representation of the Sun's atmosphere which can be used, for example, to drive space weather models. Assessing their accuracy is a complex task and there are multiple observational…

We employ Parker Solar Probe (PSP) observations during the latest solar minimum period (years 2018 -2021) to calibrate the version of the Wang-Sheeley-Arge (WSA) coronal model used in the European space weather forecasting tool EUHFORIA.…

Potential Field Source Surface (PFSS) models are widely used to study the solar corona and form the basis for solar wind forecasting, yet often fail to reproduce observed properties of coronal holes. We analyze 702 observed coronal holes…

Solar and Stellar Astrophysics · Physics 2026-01-19 Stephan G. Heinemann , Jens Pomoell , Manuela Temmer

Coronal holes are regions on the Sun's surface that map the foot-prints of open magnetic field lines. We have developed an automated routine to detect and track boundaries of long-lived coronal holes using full-disk EUV images obtained by…

Solar and Stellar Astrophysics · Physics 2015-02-24 Chris Lowder , Jiong Qiu , Robert Leamon , Yang Liu

A plethora of coronal models, from empirical to more complex magnetohydrodynamic (MHD) ones, are being used for reconstructing the coronal magnetic field topology and estimating the open magnetic flux. However, no individual solution fully…

Previous ambient solar wind (SW) validation studies have reported on discrepancies between modeled and observed SW conditions at L1. They indicated that a major source of discrepancies stems from how we model the solar corona. Thus,…

Solar and Stellar Astrophysics · Physics 2025-06-12 Satabdwa Majumdar , Martin Reiss , Karin Muglach , Charles N. Arge

Coronal holes (CHs) are regions of open magnetic flux which are the source of high speed solar wind (HSSW) streams. To date, it is not clear which aspects of CHs are of most influence on the properties of the solar wind as it expands…

Solar and Stellar Astrophysics · Physics 2018-12-12 Tadhg M. Garton , Sophie A. Murray , Peter T. Gallagher

Two extrapolation models of the solar coronal magnetic field are compared using magnetogram data from the SDO/HMI instrument. The two models, a horizontal current-current sheet-source surface (HCCSSS) model and a potential field-source…

Solar and Stellar Astrophysics · Physics 2016-05-25 William M. Arden , Aimee A. Norton , Xudong Sun , Xuepu Zhao

Global magnetic field models use as input synoptic data, which usually show "aging effects" as the longitudinal 360{\deg} information is not obtained simultaneously. Especially during times of increased solar activity, the evolution of the…

Solar and Stellar Astrophysics · Physics 2021-10-04 Stephan G. Heinemann , Manuela Temmer , Stefan J. Hofmeister , Aleksandar Stojakovic , Laurent Gizon , Dan Yang

Many scientists use coronal hole (CH) detections to infer open magnetic flux. Detection techniques differ in the areas that they assign as open, and may obtain different values for the open magnetic flux. We characterize the uncertainties…

High-speed solar wind streams emanating from coronal holes are frequently impinging on the Earth's magnetosphere causing recurrent, medium-level geomagnetic storm activity. Modeling high-speed solar wind streams is thus an essential element…

Coronal holes are usually defined as dark structures as seen in the extreme ultraviolet and X-ray spectrum which are generally associated with open magnetic field. Deriving reliably the coronal hole boundary is of high interest, as its…

We explore the use of observed polar coronal holes (CHs) to constrain the flux distribution within the polar regions of global solar magnetic field maps in the absence of reliable quality polar field observations. Global magnetic maps,…

Solar and Stellar Astrophysics · Physics 2022-06-29 Samuel J. Schonfeld , Carl J. Henney , Shaela I. Jones , Charles N. Arge

The relationship between the peak velocities of high-speed solar wind streams near Earth and the areas of their solar source regions, i.e., coronal holes, has been known since the 1970s, but it is still physically not well understood. We…

Solar and Stellar Astrophysics · Physics 2020-07-10 Stefan J. Hofmeister , Astrid M. Veronig , Stefaan Poedts , Evangelia Samara , Jasmina Magdalenic

We expand upon our paper (Rice and Yeates, 2021) which introduced `Outflow Fields': alternatives to the widely-used potential field source surface (PFSS) extrapolations of the Sun's coronal magnetic field which take into account the effect…

Solar and Stellar Astrophysics · Physics 2026-03-24 Oliver Rice , Anthony Yeates

We demonstrate the use of machine learning algorithms in combination with segmentation techniques in order to distinguish coronal holes and filaments in SDO/AIA EUV images of the Sun. Based on two coronal hole detection techniques…

The solar corona is the origin of very dynamic events that are mostly produced in active regions (AR) and coronal holes (CH). The exact location of these large-scale features can be determined by applying image-processing approaches to…

Solar and Stellar Astrophysics · Physics 2016-04-19 Saeid Arish , Mohsen Javaherian , Hossein Safari , Ali Amiri

Coronal holes are large-scale structures in the solar atmosphere that feature a reduced temperature and density in comparison to the surrounding quiet Sun and are usually associated with open magnetic fields. We perform a differential…

Solar and Stellar Astrophysics · Physics 2021-03-01 Stephan G. Heinemann , Jonas Saqri , Astrid M. Veronig , Stefan J. Hofmeister , Manuela Temmer
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