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The most probable initial magnetic configuration of a CME is a flux rope consisting of twisted field lines which fill the whole volume of a dark coronal cavity. The flux ropes can be in stable equilibrium in the coronal magnetic field for…

Solar and Stellar Astrophysics · Physics 2015-06-23 Boris Filippov , Olesya Martsenyuk , Abhishek K. Srivastava , Wahab Uddin

We present the new results of the two-dimensional numerical experiments on the cross-sectional evolution of a twisted magnetic flux tube rising from the deeper solar convection zone (-20,000 km) to the corona through the surface. The…

Solar and Stellar Astrophysics · Physics 2015-05-28 Shin Toriumi , Takaaki Yokoyama

Magnetic fields emerging from the Sun's interior carry information about physical processes of magnetic field generation and transport in the convection zone. Soon after appearance on the solar surface the magnetic flux gets concentrated in…

Solar and Stellar Astrophysics · Physics 2009-11-13 A. G. Kosovichev

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…

We propose that the coronal magnetic field, linking concentrations on the photosphere through an interwoven web of flux, embodies a scale-free network. It arises from a self-organized critical dynamics including flux emergence, the…

Astrophysics · Physics 2007-05-23 David Hughes , Maya Paczuski

We report on the results of four convective dynamo simulations with an outer coronal layer. The magnetic field is self-consistently generated by the convective motions beneath the surface. Above the convection zone, we include a polytropic…

Solar and Stellar Astrophysics · Physics 2013-11-14 Jörn Warnecke , Petri J. Käpylä , Maarit. J. Mantere , Axel Brandenburg

Coronal magnetic flux ropes are closely related to large-scale solar activities. Using a 2.5-dimensional time-dependent ideal magnetohydrodynamic (MHD) model in Cartesian coordinates, we carry out numerical simulations to investigate the…

Solar and Stellar Astrophysics · Physics 2017-12-27 Quanhao Zhang , Yuming Wang , Youqiu Hu , Rui Liu , Kai Liu , Jiajia Liu

The structure and dynamics of the solar corona is dominated by the magnetic field. In most areas in the corona magnetic forces are so dominant that all non-magnetic forces like plasma pressure gradient and gravity can be neglected in the…

Solar and Stellar Astrophysics · Physics 2021-03-24 Thomas Wiegelmann , Takashi Sakurai

By defining an appropriate field line helicity, we apply the powerful concept of magnetic helicity to the problem of global magnetic field evolution in the Sun's corona. As an ideal-magnetohydrodynamic invariant, the field line helicity is…

Solar and Stellar Astrophysics · Physics 2017-07-05 A. R. Yeates , G. Hornig

With the development of new instrumentation providing measurements of solar photospheric vector magnetic fields, we need to develop our understanding of the effects of current density on coronal magnetic field configurations. The object is…

Astrophysics · Physics 2009-11-13 S. Regnier , E. R. Priest

In the quiet solar photosphere, the mixed polarity fields form a magnetic carpet, which continuously evolves due to dynamical interaction between the convective motions and magnetic field. This interplay is a viable source to heat the solar…

Solar and Stellar Astrophysics · Physics 2014-09-16 L. P. Chitta , R. Kariyappa , A. A. van Ballegooijen , E. E. DeLuca , S. K. Solanki

We have studied three Interplanetary Coronal Mass Ejections (ICMEs) having clear signatures of magnetic cloud (MC) arrival at 1 AU and their associated solar sources during 2011 to 2013. Comparing the axial magnetic field strength (B0) of…

Solar and Stellar Astrophysics · Physics 2019-01-30 Ranadeep Sarkar , Nandita Srivastava

Magnetic fields in the sun's outer atmosphere -- the corona -- control both solar-wind acceleration and the dynamics of solar eruptions. We present the first clear observational evidence of coronal magnetic nulls in off-limb linearly…

Force-free extrapolations are widely used to study the magnetic field in the solar corona based on surface measurements. The extrapolations assume that the ratio of internal energy of the plasma to magnetic energy, the plasma-beta is…

Solar and Stellar Astrophysics · Physics 2015-11-25 H. Peter , J. Warnecke , L. P. Chitta , R. H. Cameron

We aim to better characterize the conditions of the solar corona, especially with respect to the occurrence of confined and eruptive flares. In this work, we model the coronal evolution around 231 large flares observed during solar cycle…

Solar and Stellar Astrophysics · Physics 2025-01-29 Julia K. Thalmann , Manu Gupta , Astrid M. Veronig , Yang Liu

We study the magnetic field and current structure associated with a coronal loop. Through this we investigate to what extent the assumptions of a force-free magnetic field break down and where they might be justified. We analyse a 3D MHD…

Solar and Stellar Astrophysics · Physics 2017-12-05 Jörn Warnecke , Feng Chen , Sven Bingert , Hardi Peter

We investigate the time evolution of relative elemental abundances in the context of the first ionization potential effect focusing on an active region. Our aim is to characterize this evolution in different types of solar active region…

Solar and Stellar Astrophysics · Physics 2026-02-11 T. Varesano , D. M. Hassler , N. Zambrana Prado , J. M. Laming , J. Plowman , D. J. Knipp , M. Molnar , K. Barczynski , The SPICE consortium

We present in this Letter the first global comparison between traditional line-tied steady state magnetohydrodynamic models and a new, fully time-dependent thermodynamic magnetohydrodynamic simulation of the global corona. The maps are…

Solar and Stellar Astrophysics · Physics 2023-06-22 Emily I. Mason , Roberto Lionello , Cooper Downs , Jon A. Linker , Ronald M. Caplan

Solar flare simulations are commonly initialised using non-linear force free field (NLFF) extrapolations derived from photospheric vector magnetograms. However, the force free assumption neglects plasma forces and may limit the available…

Solar and Stellar Astrophysics · Physics 2026-05-15 W. Bate , M. Gordovskyy , A. Prasad , A. S. Brun , A. Strugarek , M. V. Sieyra , P. Browning , S. Inoue , K. Matsumoto , A. Roddanavar

Magnetic fields generated in the Sun's interior by the solar dynamo mechanism drive solar activity over a range of time-scales. While space-based observations of the Sun's corona exist only for few decades, direct sunspot observations exist…

Solar and Stellar Astrophysics · Physics 2023-07-03 Soumyaranjan Dash , Dibyendu Nandy , Ilya Usoskin
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