English
Related papers

Related papers: On the extrapolation of magneto-hydro-static equil…

200 papers

Context. On the sun, the magnetic field vector is measured routinely only in the photosphere. By using these photospheric measurements as boundary condition, we developed the magnetohydrostatic (MHS) extrapolation to model the solar…

Solar and Stellar Astrophysics · Physics 2019-11-20 Xiaoshuai Zhu , Thomas Wiegelmann

Understanding structures and evolutions of the magnetic fields and plasma in multiple layers on the Sun is very important. A force-free magnetic field which is an accurate approximation of the solar corona due to the low plasma $\beta$ has…

Solar and Stellar Astrophysics · Physics 2022-03-30 Xiaoshuai Zhu , Thomas Neukirch , Thomas Wiegelmann

With current observational methods it is not possible to directly measure the magnetic field in the solar corona with sufficient accuracy. Therefore, coronal magnetic field models have to rely on extrapolation methods using photospheric…

Solar and Stellar Astrophysics · Physics 2025-04-24 Lilli Nadol , Thomas Neukirch

Context. High resolution magnetic field measurements are routinely done only in the solar photosphere. Higher layers like the chromosphere and corona can be modeled by extrapolating the photospheric magnetic field upward. In the solar…

Solar and Stellar Astrophysics · Physics 2020-08-26 Xiaoshuai Zhu , Thomas Wiegelmann , Sami Solanki

Aims. We aim to develop a fast and consistent extrapolation method to model multiple layers of the solar atmosphere. Methods. The new approach combines the magnetohydrostatic (MHS) extrapolation which models the solar low atmosphere in a…

Solar and Stellar Astrophysics · Physics 2022-02-02 Xiaoshuai Zhu , Thomas Wiegelmann

For the extrapolation of magnetic fields into the solar corona from measurements taken in the photosphere (or chromosphere) force-free magnetic fields are typically used. This does not take into account that the lower layers of the solar…

Solar and Stellar Astrophysics · Physics 2020-01-08 Thomas Neukirch , Thomas Wiegelmann

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

Magnetic field in the solar corona is usually extrapolated from photospheric vector magnetogram using a nonlinear force-free field (NLFFF) model. NLFFF extrapolation needs a considerable effort to be devoted for its numerical realization.…

Solar and Stellar Astrophysics · Physics 2015-06-04 Chaowei Jiang , Xueshang Feng

A nonlinear force-free field (NLFFF) extrapolation is widely used to reconstruct the three-dimensional magnetic field in the solar corona from the observed photospheric magnetic field. However, the pressure gradient and gravitational forces…

Solar and Stellar Astrophysics · Physics 2020-03-04 Takahiro Miyoshi , Kanya Kusano , Satoshi Inoue

Magnetic field extrapolation is a fundamental tool to reconstruct the three-dimensional magnetic field above the solar photosphere. However, the prevalently used force-free field model might not be applicable in the lower atmosphere with…

Solar and Stellar Astrophysics · Physics 2023-07-12 Fu Yu , Jie Zhao , Yang Su , Xiaoshuai Zhu , Yang Guo , Jinhua Shen , Hui Li

In this work we describe a numerical optimization method for computing stationary MHD-equilibria. The newly developed code is based on a nonlinear force-free optimization principle. We apply our code to model the solar corona using synoptic…

Solar and Stellar Astrophysics · Physics 2020-11-11 Thomas Wiegelmann , Thomas Neukirch , Dieter H. Nickeler , Iulia Chifu

The coronal magnetic field is an important quantity because the magnetic field dominates the structure of the solar corona. Unfortunately direct measurements of coronal magnetic fields are usually not available. The photospheric magnetic…

Astrophysics · Physics 2009-06-25 T. Wiegelmann

Non-linear force-free extrapolations are a common approach to estimate the 3D topology of coronal magnetic fields based on photospheric vector magnetograms. The force-free assumption is a valid approximation at coronal heights, but for the…

Our aim is to model the 3D magnetic field structure of the upper solar atmosphere, including regions of non-negligible plasma beta. We use high-resolution photospheric magnetic field measurements from SUNRISE/IMaX as boundary condition for…

Solar and Stellar Astrophysics · Physics 2015-12-09 T. Wiegelmann , T. Neukirch , D. H. Nickeler , S. K. Solanki , V. Martinez Pillet , J. M. Borrero

Aims. Linear magnetohydrostatic (MHS) models of solar magnetic fields balance plasma pressure gradients, gravity and Lorentz forces where the current density is composed of a linear force-free component and a cross-field component that…

Solar and Stellar Astrophysics · Physics 2013-07-26 David MacTaggart , Abdulaziz Elsheikh , James McLaughlin , Radostin Simitev

Routine measurements of the solar magnetic field are mainly carried out in the photosphere. Therefore, one has to infer the field strength in the higher layers of the solar atmosphere from the measured photospheric field based on the…

Solar and Stellar Astrophysics · Physics 2015-05-20 Tilaye Tadesse , T. Wiegelmann , B. Inhester , A. Pevtsov

We introduce to the stellar physics community a method of modelling stellar coronae that can be considered to be an extension of the potential field. In this approach, the magnetic field is coupled to the background atmosphere. The model is…

Solar and Stellar Astrophysics · Physics 2015-12-23 David MacTaggart , Scott Gregory , Thomas Neukirch , Jean-Francois Donati

Three-dimensional (3D) magnetic field in the solar atmosphere provides crucial information to understand the explosive phenomenon such as solar flares and coronal mass ejections. Since it is still hard that we determine the 3D magnetic…

Solar and Stellar Astrophysics · Physics 2026-01-07 Daiki Yamasaki , Takahiro Miyoshi , Satoshi Inoue

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

Context. Understanding the 3D magnetic field as well as the plasma in the chromosphere and transition region is important. One way is to extrapolate the magnetic field and plasma from the routinely measured vector magnetogram on the…

Solar and Stellar Astrophysics · Physics 2021-01-04 Xiaoshuai Zhu , Thomas Wiegelmann , Bernd Inhester
‹ Prev 1 2 3 10 Next ›