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Related papers: Three-dimensional solar active region magnetohydro…

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The aim of this work is to investigate and characterise particle behaviour in an (observationally-driven) 3D MHD model of the solar atmosphere above a slowly evolving, non-flaring active region. We use a relativistic guiding-centre particle…

Solar and Stellar Astrophysics · Physics 2016-02-17 J. Threlfall , Ph. -A. Bourdin , T. Neukirch , C. E. Parnell

Three-dimensional (3D) radiative magnetohydrodynamics (MHD) simulations are the only way to model stellar atmospheres without any ad hoc parameterisations. Several 3D radiative MHD codes have achieved good quantitative agreement with…

Magnetic holes (MHs) are coherent structures characterized by a strong and localized magnetic field amplitude dip, commonly observed in the solar wind and planetary magnetosheaths. These structures come in different sizes, from…

Space Physics · Physics 2025-05-30 Joaquín Espinoza-Troni , Giuseppe Arrò , Felipe A Asenjo , Pablo S Moya

Solar eruptions arise from instabilities or loss of equilibria in the solar atmosphere, but routinely inferring the precise magnetic and plasma properties that lead to eruptions is not currently practical using synoptic solar observations.…

Solar and Stellar Astrophysics · Physics 2026-01-16 Lucas A. Tarr , N. Dylan Kee , James E. Leake , Mark G. Linton , Peter W. Schuck

Linking solar wind properties to the activities and characteristics of its source regions can enhance our understanding of its origin and generation mechanisms. Using the Mount Wilson magnetic classification (MWMC), we categorize all active…

Solar and Stellar Astrophysics · Physics 2025-10-13 Xinzheng Shi , Hui Fu , Zhenghua Huang , Limei Yan , Qi Liu , Lidong Xia

Solar active regions (ARs) that produce strong flares and coronal mass ejections (CMEs) are known to have a relatively high non-potentiality and are characterized by delta-sunspots and sheared magnetic structures. In this study, we conduct…

Solar and Stellar Astrophysics · Physics 2017-11-29 Shin Toriumi , Shinsuke Takasao

A representation of the static MHD equilibrium system in coordinates connected with magnetic surfaces is suggested. It is used for producing families of non-trivial 3D exact solutions of isotropic and anisotropic plasma equilibria in…

Mathematical Physics · Physics 2007-05-23 Alexei F. Cheviakov

Due to their characteristic temperature and density, loop structures in active regions (ARs) can be seen bright in extreme ultraviolet (EUV) and soft X-ray images. The semiempirical determination of the three-dimensional (3D) distribution…

Solar and Stellar Astrophysics · Physics 2020-12-16 F. A. Nuevo , C. Mac Cormack , M. López Fuentes , A. M. Vásquez , C. H. Mandrini

Azimuthal structures emerging in beam-generated partially magnetized plasmas are investigated using three-dimensional particle-in-cell/Monte Carlo collision simulations. Two distinct instability regimes are identified at low pressures. When…

Plasma Physics · Physics 2025-07-01 Jian Chen , Andrew T. Powis , Igor D. Kaganovich , Zhibin Wang

The magnetic fields in the solar corona are generally neither force-free nor axisymmetric and have complex dynamics that are difficult to characterize. Here we simulate the topological evolution of solar coronal magnetic field lines (MFLs)…

Solar and Stellar Astrophysics · Physics 2017-05-09 A. Prasad , R. Bhattacharyya , Sanjay Kumar

The chapter "Solar Active Region Electric Currents Before and During Eruptive Flares" is a discussion on electric currents in the pre-eruption state and in the course of eruptions of solar magnetic structures, using information from solar…

Solar and Stellar Astrophysics · Physics 2019-03-13 Brigitte Schmieder , Guillaume Aulanier

We describe a new method to include magnetic fields into smooth particle hydrodynamics. The derivation of the self-gravitating hydrodynamics equations from a variational principle is discussed in some detail. The non-dissipative magnetic…

Astrophysics · Physics 2008-02-05 S. Rosswog , D. J. Price

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

We present initial results of the first self-consistent numerical model of the outer magnetosphere of a pulsar. By using the relativistic ``particle-in-cell'' method with special boundary conditions to represent plasma dynamics in 3D, we…

Astrophysics · Physics 2007-05-23 Anatoly Spitkovsky , Jonathan Arons

A simplified non-linear numerical model for the development of incompressible magnetohydrodynamics (MHD) in the presence of a strong magnetic field B0 and stratification, nicknamed Shell-Atm, is presented. In planes orthogonal to the mean…

Astrophysics · Physics 2011-02-11 E. Buchlin , M. Velli

Context. Active regions (ARs) appear in the solar atmosphere as a consequence of the emergence of magnetic flux tubes. The presence of elongated magnetic polarities in line-of-sight (LOS) magnetograms indicates the existence of twist in the…

Solar and Stellar Astrophysics · Physics 2022-09-14 M. Poisson , F. Grings , C. H. Mandrini , M. López-Fuentes , P. Démoulin

Recent studies indicate that a small number of rogue solar active regions (ARs) may have a significant impact on the end-of-cycle polar field and the long-term behavior of solar activity. The impact of individual ARs can be qualified based…

Solar and Stellar Astrophysics · Physics 2024-05-13 Ruihui Wang , Jie Jiang , Yukun Luo

We carry out 3D and 2D PIC-simulations of the expansion of a magnetized plasma that initially uniformly fills a half-space and contains a semi-cylindrical region of heated electrons elongated along the surface of the plasma boundary. This…

There is considerable observational evidence of implosion of magnetic loop systems inside solar coronal active regions following high energy events like solar flares. In this work, we propose that such collapse can be modeled in three…

Solar and Stellar Astrophysics · Physics 2017-12-27 Aveek Sarkar , Bhargav Vaidya , Soumitra Hazra , Jishnu Bhattacharyya

Pillars of Creation, one of the most recognized objects in the sky, are believed to be associated with the formation of young stars. However, so far, the formation and maintenance mechanism for the pillars are still not fully understood due…

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