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Related papers: Coronal Hole Detection and Open Magnetic Flux

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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…

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

The heliospheric magnetic field is of pivotal importance in solar and space physics. The field is rooted in the Sun's photosphere, where it has been observed for many years. Global maps of the solar magnetic field based on full disk…

Solar and Stellar Astrophysics · Physics 2017-10-18 J. A. Linker , R. M. Caplan , C. Downs , P Riley , Z Mikic , R. Lionello , C. J. Henney , C. N. Arge , Y. Liu , M. L. Derosa , A. Yeates , M. J. Owens

The solar magnetic fields emerging from the photosphere into the chromosphere and corona are comprised of a combination of "closed" and "open" fields. The closed magnetic field lines are defined as those having both ends rooted in the solar…

Solar and Stellar Astrophysics · Physics 2023-04-18 C. Nick Arge , Andrew Leisner , Samantha Wallace , Carl J. Henney

Over the solar-activity cycle, there are extended periods where significant discrepancies occur between the spacecraft-observed total (unsigned) open magnetic flux and that determined from coronal models. In this article, the total open…

Solar and Stellar Astrophysics · Physics 2019-04-01 S. Wallace , C. N. Arge , M. Pattichis , R. A. Hock-Mysliwiec , C. J. Henney

Coronal holes (CHs) are regions with unbalanced magnetic flux, and have been associated with open magnetic field (OMF) structures. However, it has been reported that some CHs do not intersect with OMF regions. To investigate the…

Solar and Stellar Astrophysics · Physics 2022-07-27 Guan-Han Huang , Chia-Hsien Lin , Lou-Chuang Lee

We investigate the relationship between solar coronal holes and open-field regions using three-dimensional radiative magnetohydrodynamic (MHD) simulations combined with remote-sensing observations from the Solar Dynamics Observatory (SDO).…

Solar and Stellar Astrophysics · Physics 2025-10-31 Haruhisa Iijima

Coronal holes (CH) are regions of open magnetic fields that appear as dark areas in the solar corona due to their low density and temperature compared to the surrounding quiet corona. To date, accurate identification and segmentation of CHs…

Solar and Stellar Astrophysics · Physics 2019-03-15 Tadhg M. Garton , Peter T. Gallagher , Sophie A. Murray

As the observational signature of the footprints of solar magnetic field lines open into the heliosphere, coronal holes provide a critical measure of the structure and evolution of these lines. Using a combination of Solar and Heliospheric…

Solar and Stellar Astrophysics · Physics 2016-12-23 Chris Lowder , Jiong Qiu , Robert Leamon

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

We develop a reliable, fully automatic method for the detection of coronal holes, that provides consistent full-disk segmentation maps over the full solar cycle and can perform in real-time. We use a convolutional neural network to identify…

Solar and Stellar Astrophysics · Physics 2021-08-09 R. Jarolim , A. M. Veronig , S. Hofmeister , S. G. Heinemann , M. Temmer , T. Podladchikova , K. Dissauer

Employing Big Bear Solar Observatory (BBSO) deep magnetograms and H${\alpha}$ images in a quiet region and a coronal hole, observed on September 14 and 16, 2004, respectively, we have explored the magnetic flux emergence, disappearance and…

Astrophysics · Physics 2010-11-11 Jun Zhang , Jun Ma , Haimin Wang

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…

Coronal holes are the observational manifestation of the solar magnetic field open to the heliosphere and are of pivotal importance for our understanding of the origin and acceleration of the solar wind. Observations from space missions…

A joint campaign of various space-borne and ground-based observatories, comprising the Japanese Hinode mission (HOP~338, 20\,--\,30~September 2017), the GREGOR solar telescope, and the \textit{Vacuum Tower Telescope} (VTT), investigated…

Coronal Holes (CHs) are large-scale, low-density regions in the solar atmosphere which may expel high-speed solar wind streams that incite hazardous, geomagnetic storms. Coronal and solar wind models can predict these high-speed streams and…

Coronal holes (CHs) are magnetically open regions that allow hot coronal plasma to escape from the Sun and form the high-speed solar wind. This wind can interact with Earth's magnetic field. For this reason, developing an accurate…

Solar and Stellar Astrophysics · Physics 2025-09-16 Jeremy A. Grajeda , Laura E. Boucheron , Michael S. Kirk , Andrew Leisner , C. Nick Arge , Jaime A. Landeros

Coronal holes (CH) are regions of open magnetic field lines in the solar corona and the source of fast solar wind. Understanding the evolution of coronal holes is critical for solar magnetism as well as for accurate space weather forecasts.…

Space Physics · Physics 2018-05-02 Amr Hamada , Timo Asikainen , Ilpo Virtanen , Kalevi Mursula

Parameters of magnetic flux distribution inside low-latitude coronal holes (CHs) were analyzed. A statistical study of 44 CHs based on Solar and Heliospheric Observatory (SOHO)/MDI full disk magnetograms and SOHO/EIT 284\AA images showed…

Solar and Stellar Astrophysics · Physics 2015-05-13 Valentina Abramenko , Vasyl Yurchyshyn , Hiroko Watanabe

We investigate the statistics of 288 low-latitude coronal holes extracted from SDO/AIA-193 filtergrams over the time range 2011/01/01 to 2013/12/31. We analyse the distribution of characteristic coronal hole properties, such as the areas,…

Solar and Stellar Astrophysics · Physics 2017-02-08 S. J. Hofmeister , A. Veronig , M. A. Reiss , M. Temmer , S. Vennerstrom , B. Vršnak , B. Heber
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