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Related papers: Reconstructing coronal hole areas with EUHFORIA an…

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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

Coronal mass ejections (CMEs) are a manifestation of the Sun's eruptive nature. They can have a great impact on Earth, but also on human activity in space and on the ground. Therefore, modelling their evolution as they propagate through…

Solar and Stellar Astrophysics · Physics 2021-08-04 E. Asvestari , J. Pomoell , E. Kilpua , S. Good , T. Chatzistergos , M. Temmer , E. Palmerio , S. Poedts , J. Magdalenic

In this study, we describe and evaluate shape measures for distinguishing between coronal holes and filament channels as observed in Extreme Ultraviolet (EUV) images of the Sun. For a set of well-observed coronal hole and filament channel…

Solar and Stellar Astrophysics · Physics 2014-08-13 M. Reiss , M. Temmer , T. Rotter , S. J. Hofmeister , A. M. Veronig

X-ray and EUV observations are an important diagnostic of various plasma parameters of the solar atmosphere during solar flares. Soft X-ray and EUV observations often show coronal sources near the top of flaring loops, while hard X-ray…

Solar and Stellar Astrophysics · Physics 2015-06-11 Marina Battaglia , Eduard P. Kontar

The distribution of the coronal electron density at different distances from the Sun strongly influences the physical processes in the solar corona and is therefore a very important topic in solar physics. Most methods, including radio…

Using detrended fluctuation analysis (DFA) and rescaled range (R/S) analysis, we investigate the scaling properties of EUV intensity fluctuations of low-latitude coronal holes (CHs) and neighboring quiet-Sun (QS) regions in signals obtained…

Solar and Stellar Astrophysics · Physics 2020-01-08 Ana Cristina Cadavid , Mari Paz Miralles , Kristine Romich

It has long been known that the high-speed stream (HSS) peak velocity at Earth directly depends on the area of the coronal hole (CH) on the Sun. Different degrees of association between the two parameters have been shown by many authors. In…

A lower bound on unbiased estimates of wavefront errors (WFE) is presented for the linear regime of small perturbation and active control of a high-contrast region (dark hole). Analytical approximations and algorithms for computing the…

Instrumentation and Methods for Astrophysics · Physics 2021-10-13 Leonid Pogorelyuk , Laurent Pueyo , Jared R. Males , Kerri Cahoy , N. Jeremy Kasdin

The study of the evolution of coronal holes (CHs) is especially important in the context of high-speed solar wind streams (HSS) emanating from them. Stream interaction regions may deliver large amount of energy into the Earths system, cause…

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

Coronal Mass Ejections (CMEs) are the primary source of strong space weather disturbances at Earth. Their geoeffectiveness is largely determined by their dynamic pressure and internal magnetic fields, for which reliable predictions at Earth…

Solar and Stellar Astrophysics · Physics 2019-06-26 Camilla Scolini , Luciano Rodriguez , Marilena Mierla , Jens Pomoell , Stefaan Poedts

The energy input into the lower solar corona by flare evaporation events has been modeled according to the available observations for quiet regions. The question is addressed whether such heating events can provide the observed average…

Astrophysics · Physics 2008-11-26 U. Mitra-Kraev , A. O. Benz

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

The potential field source surface (PFSS) method is a widely used magnetic field extrapolation technique in the space weather community. The only free parameter in the PFSS method is the source-surface height ($R_{\rm SS}$), beyond which…

Solar and Stellar Astrophysics · Physics 2025-10-16 Munehito Shoda , Kyogo Tokoro , Daikou Shiota , Shinsuke Imada

The Potential Field Source Surface (PFSS) model is the most used approach for extrapolating the global coronal magnetic field, offering efficiency and strong performance at large scales. However, PFSS assumes a potential coronal field, so…

Solar and Stellar Astrophysics · Physics 2026-03-23 C. Antonio , I. Chifu , R. Gafeira , J. J. G. Lima

We present a model for the intensity of optically thin EUV emission for a plasma atmosphere. We apply our model to the solar corona as observed using the six optically thin EUV channels of the SDO/AIA instrument. The emissivity of the…

Solar and Stellar Astrophysics · Physics 2020-03-31 D. J. Pascoe , A. Smyrli , T. Van Doorsselaere

This paper aims to present the time-dependent coupling between the coronal model COolfluid COroNal UnsTructured (COCONUT) and the heliospheric forecasting tool EUHFORIA. We perform six COCONUT simulations where a flux rope is implemented at…

Solar and Stellar Astrophysics · Physics 2024-12-02 L. Linan , T. Baratashvili , A. Lani , B. Schmieder , M. Brchnelova , J. H. Guo , S. Poedts

Aims. We present the validation results for arrival times and geomagnetic impact of Coronal Mass Ejections (CMEs), using the cone and spheromak CME models implemented in EUropean Heliospheric FORecasting Information Asset (EUHFORIA).…

Risaliti and Lusso have compiled X-ray and UV flux measurements of 1598 quasars (QSOs) in the redshift range $0.036 \leq z \leq 5.1003$, part of which, $z \sim 2.4 - 5.1$, is largely cosmologically unprobed. In this paper we use these QSO…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-28 Narayan Khadka , Bharat Ratra

We present a novel global 3-D coronal MHD model called COCONUT, polytropic in its first stage and based on a time-implicit backward Euler scheme. Our model boosts run-time performance in comparison with contemporary MHD-solvers based on…

Solar and Stellar Astrophysics · Physics 2022-08-31 Barbara Perri , Peter Leitner , Michaela Brchnelova , Tinatin Baratashvili , Blazej Kuzma , Fan Zhang , Andrea Lani , Stefaan Poedts