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Context. Observations of many active regions show a slow systematic outflow/upflow from their edges lasting from hours to days. At present no physical explanation has been proven, while several suggestions have been put forward. Aims. This…

Solar and Stellar Astrophysics · Physics 2021-08-25 K. Galsgaard , M. S. Madjarska , K. Vanninathan , Z. Huang , M. Presmann

The modeling of electric machines and power transformers typically involves systems of nonlinear magnetostatics or -quasistatics, and their efficient and accurate simulation is required for the reliable design, control, and optimization of…

Numerical Analysis · Mathematics 2024-08-23 Herbert Egger , Felix Engertsberger , Bogdan Radu

We present the first numerical simulations of the solar interior to exhibit a tachocline consistent with the Gough and McIntyre (1998) model. We find nonlinear, axisymmetric, steady-state numerical solutions in which: (1) a large-scale…

Solar and Stellar Astrophysics · Physics 2015-06-15 Luis A. Acevedo-Arreguin , Pascale Garaud , Toby S. Wood

Using solar vector magnetograms of the highest available spatial resolution and signal-to-noise ratio we perform a detailed study of electric current patterns in two solar active regions: a flaring/eruptive, and a flare-quiet one. We aim to…

Solar and Stellar Astrophysics · Physics 2015-06-11 Manolis K. Georgoulis , Viacheslav S. Titov , Zoran Mikic

Using the H$\alpha$ data from the New Vacuum Solar Telescope (NVST) at the Fuxian Solar Observatory together with multi-wavelength images and magnetograms obtained by Solar Dynamics Observatory (SDO), we study the detailed process of three…

Solar and Stellar Astrophysics · Physics 2020-01-08 Guorong Chen , Xiaoli Yan

The variations of the 3-D coronal magnetic fields associated with the X3.4-class flare of active region 10930 are studied in this paper. The coronal magnetic field data are reconstructed from the photospheric vector magnetograms obtained by…

Solar and Stellar Astrophysics · Physics 2016-05-03 Han He , Huaning Wang , Yihua Yan , P. F. Chen , Cheng Fang

In this paper, the statistical studies on the force-freeness of photosphere magnetic fields are given. The studies are based on the vector magnetic fields observed by Solar Optical Telescope/Spectro-Polarimeter (SOT/SP) on board Hinode.…

Solar and Stellar Astrophysics · Physics 2019-02-04 S. Liu , J. Hao

A magneto-hydrostatic model is constructed with spectropolarimetric properties close to those of solar photospheric magnetic bright points. Results of solar radiative magneto-convection simulations are used to produce the spatial structure…

Solar and Stellar Astrophysics · Physics 2015-05-18 S. Shelyag , M. Mathioudakis , F. P. Keenan , D. B. Jess

The physics of solar flares occurring on the Sun is highly complex and far from fully understood. However, observations show that solar eruptions are associated with the intense kilogauss fields of active regions, where free energies are…

Solar and Stellar Astrophysics · Physics 2024-01-26 Bach Viet Do , Yang Chen , XuanLong Nguyen , Ward Manchester

Using a recently proposed nonlinear force-free method designed for single vector magnetograms of solar active regions we calculate the instantaneous free magnetic energy and relative magnetic helicity budgets in 162 vector magnetograms…

Solar and Stellar Astrophysics · Physics 2015-06-11 Kostas Tziotziou , Manolis K. Georgoulis , Nour-Eddine Raouafi

The minimum-energy configuration for the magnetic field above the solar photosphere is curl-free (hence, by Ampere's law, also current-free), so can be represented as the gradient of a scalar potential. Since magnetic fields are divergence…

Solar and Stellar Astrophysics · Physics 2016-06-20 Brian T. Welsch , George H. Fisher

This paper uses linear magnetohydrodynamics to model resonant absorption in coronal plasma with a Cartesian coordinate system. We impose line-tied boundary conditions and tilt the background magnetic field to be oblique to the transition…

Solar and Stellar Astrophysics · Physics 2021-04-22 A. P. K. Prokopyszyn , A. N. Wright , A. W. Hood

The solar active region NOAA 11719 produced a large two-ribbon flare on 11 April 2013. We have investigated the sudden variations in the photospheric magnetic fields in this active region during the flare employing the magnetograms obtained…

Solar and Stellar Astrophysics · Physics 2016-10-27 Brajesh Kumar , A. Raja Bayanna , P. Venkatakrishnan , Shibu K. Mathew

In this review many of the well known tools for the analysis of Complex systems are used in order to study the global coupling of the turbulent convection zone with the solar atmosphere where the magnetic energy is dissipated explosively.…

Solar and Stellar Astrophysics · Physics 2016-11-03 Loukas Vlahos , Heinz Isliker

We update our earlier study in [1], which was inspired by the 2002 SNO data, on the implications of the results of the solar neutrino experiments for the predictions of the effective Majorana mass in neutrinoless double beta-decay, |<m>|.…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. Pascoli , S. T. Petcov

Statistical properties of the Sun's photospheric turbulent magnetic field, especially those of the Active Regions (ARs), have been studied using the line-of-sight data from magnetograms taken by SOHO and several other instruments (see e.g.…

Solar and Stellar Astrophysics · Physics 2013-07-17 Shiva Kumar. Malapaka , Wolf-Christian Mueller

The global magnetic field in the solar corona is known to contain free magnetic energy and magnetic helicity above that of a current-free (potential) state. But the strength of this non-potentiality and its evolution over the solar cycle…

Solar and Stellar Astrophysics · Physics 2024-05-24 Anthony R. Yeates

In this study, we introduce a novel approach for deriving the solution of the ideal force-free steady-state pulsar magnetosphere in three dimensions. Our method involves partitioning the magnetosphere into the regions of closed and open…

High Energy Astrophysical Phenomena · Physics 2024-01-17 Ioannis Dimitropoulos , Ioannis Contopoulos , Vassilis Mpisketzis , Evangelos Chaniadakis

Context. Data-constrained models incorporate observed photospheric magnetic fields. However, due to the lack of magnetic field information in the rest of the solar atmosphere, models rely on extrapolations that, in most cases, neglect the…

Solar and Stellar Astrophysics · Physics 2026-05-20 M. V. Sieyra , A. Strugarek , A. Prasad , A. Wagner , P. Démoulin , F. Moreno-Insertis , A. J. Finley , R. Joshi , A. Blaise , A. S. Brun , E. Buchlin

Many studies of the solar corona have shown that the observed X-ray luminosity is well correlated with the total unsigned magnetic flux. In this paper we present results from the extensive numerical modeling of active regions observed with…

Astrophysics · Physics 2016-08-30 Harry P. Warren , Amy R. Winebarger
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