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The coupling between small and large scale structures and processes on the Sun and in the heliosphere is important in the relation to the global magnetic configuration. Thin heliospheric current sheets play the leading role in this respect.…

Solar and Stellar Astrophysics · Physics 2012-12-24 Igor Veselovsky , Olga Panasenco

Vector displacements expressed in spherical coordinates are proposed. They correspond to electromagnetic fields in vacuum that globally rotate about an axis and display many circular patterns on the surface of a sphere. The fields basically…

Classical Physics · Physics 2021-06-11 Daniele Funaro

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

The nonlinear force-free field (NLFFF) model is often used to describe the solar coronal magnetic field, however a series of earlier studies revealed difficulties in the numerical solution of the model in application to photospheric…

We present a novel numerical method that allows the calculation of nonlinear force-free magnetostatic solutions above a boundary surface on which only the distribution of the normal magnetic field component is given. The method relies on…

Solar and Stellar Astrophysics · Physics 2015-05-20 Ioannis Contopoulos , Constantinos Kalapotharakos , Manolis Georgoulis

We show that the use of the electromagnetic inverse source framework offers great flexibility in the design of metasurfaces. In particular, this approach is advantageous for antenna design applications where the goal is often to satisfy a…

Applied Physics · Physics 2019-10-17 Trevor Brown , Chaitanya Narendra , Yousef Vahabzadeh , Christophe Caloz , Puyan Mojabi

Measurements of magnetic fields and electric currents in the pre-eruptive corona are crucial to study solar eruptive phenomena, like flare and coronal mass ejections(CMEs). However, spectro-polarimetric measurements of certain photospheric…

Solar and Stellar Astrophysics · Physics 2015-06-12 Tilaye Tadesse , T. Wiegelmann , B. Inhester , K. Olson , P. J. MacNeice , A. Pevtsov

In this paper a new method is derived for constructing electromagnetic surface sources for stationary axisymmetric electrovac spacetimes endowed with non-smooth or even discontinuous Ernst potentials. This can be viewed as a generalization…

General Relativity and Quantum Cosmology · Physics 2016-08-31 L. Fernandez-Jambrina

Global coronal models seek to produce an accurate physical representation of the Sun's atmosphere which can be used, for example, to drive space weather models. Assessing their accuracy is a complex task and there are multiple observational…

We investigate some important physical aspects of a recently presented interior solution for the Kerr metric. It is shown that, as in the spherically symmetric case, there is a specific limit for the maximal value of the surface potential…

General Relativity and Quantum Cosmology · Physics 2017-07-28 L. Herrera , J. L. Hernandez-Pastora

By comparing a magneto-frictional model of the low coronal magnetic field to a potential-field source-surface model, we investigate the possible impact of non-potential magnetic structure on empirical solar-wind models. These empirical…

Solar and Stellar Astrophysics · Physics 2015-12-09 S. J. Edwards , A. R. Yeates , F. -X. Bocquet , D. H. Mackay

Graphitic micro-particles coated with thin layers in solution are technologically interesting as they can be manipulated with electric fields. Modeling the electrical manipulation of submerged layered micro-particles analytically or…

Soft Condensed Matter · Physics 2018-02-26 Johnny Nguyen , Jonathan G. Underwood , Isabel Llorente García

Presently, many models of the coronal magnetic field rely on photospheric vector magnetograms but these data have been shown to be problematic as the sole boundary information for nonlinear force-free field (NLFFF) extrapolations. Magnetic…

Solar and Stellar Astrophysics · Physics 2021-06-29 A. Malanushenko , C. J. Schrijver , M. L. DeRosa , M. S. Wheatland , S. A. Gilchrist

Electromagnetic metasurfaces offer the capability to realize almost arbitrary power conserving field transformations. These field transformations are governed by the generalized sheet transition conditions, which relate the tangential…

Applied Physics · Physics 2020-11-19 Stewart Pearson , Sean V. Hum

We propose a powerful approach to solve Laplace's equation for point sources near a spherical object. The central new idea is to use prolate spheroidal solid harmonics, which are separable solutions of Laplace's equation in spheroidal…

Classical Physics · Physics 2017-03-22 Matt Majic , Baptiste Auguie , Eric C. Le Ru

We describe a newly developed code for the extrapolation of nonlinear force-free coronal magnetic fields in spherical coordinates. The program uses measured vector magnetograms on the solar photosphere as input and solves the force-free…

Astrophysics · Physics 2008-11-26 Thomas Wiegelmann

The internal dynamics of the Sun generate magnetic and plasma structures in the photosphere and overlying atmosphere across a wide range of spatial scales. Identifying the critical spatial scale is essential for interpreting physical…

Solar and Stellar Astrophysics · Physics 2026-04-14 Ananya Hore , Prantika Bhowmik

We numerically examine the exterior solution of spherically symmetric and static configuration in scalar-tensor theories by using the nonminimally coupled scalar field with zero potential as our sample model. Our main purpose in this work…

General Relativity and Quantum Cosmology · Physics 2023-03-20 A. Savaş Arapoğlu , Sermet Çağan , A. Emrah Yükselci

In the recent years, global coronal models have experienced an ongoing increase in popularity as tools for forecasting solar weather. Within the domain of up to 21.5Rsun, magnetohydrodynamics (MHD) is used to resolve the coronal structure…

Solar and Stellar Astrophysics · Physics 2022-11-30 Michaela Brchnelova , Błażej Kuźma , Barbara Perri , Andrea Lani , Stefaan Poedts

This paper aims to develop the mathematical representation of a surface generated by elliptical arcs joining the sides of a regular polygon to a point lying vertically upward on the central axis of the polygon. The volume of the…

History and Overview · Mathematics 2020-09-02 Shahid Saeed Siddiqi , Abdul Rauf Nizami