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Related papers: Toroidal equilibria in spherical coordinates

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The equilibrium of an axisymmetric magnetically confined plasma with anisotropic resistivity and toroidal flow is investigated in the framework of magnetohydrodynamics (MHD). The stationary states are determined by an elliptic differential…

Plasma Physics · Physics 2015-06-26 G. Poulipoulis , G. N. Throumoulopoulos , H. Tasso

Upper main sequence stars, white dwarfs and neutron stars are known to possess stable, large-scale magnetic fields. Numerical works have confirmed that stable MHD equilibria can exist in non-barotropic, stably stratified stars. On the other…

Solar and Stellar Astrophysics · Physics 2015-06-23 C. Armaza , A. Reisenegger , J. A. Valdivia

We consider the periodic problem for two-fluid non-isentropic Euler-Maxwell systems in plasmas. By means of suitable choices of symmetrizers and an induction argument on the order of the time-space derivatives of solutions in energy…

Analysis of PDEs · Mathematics 2018-08-15 Yue-Hong Feng , Xin Li , Shu Wang

In this paper we provide sharp criteria for linear stability or instability of equilibria of collisionless plasmas in the presence of boundaries. Specifically, we consider the relativistic Vlasov-Maxwell system with specular reflection at…

Analysis of PDEs · Mathematics 2011-12-21 Toan Nguyen , Walter A. Strauss

The phenomenon of quantum vacuum polarization in the presence of a gravitational field is well understood and is expected to have a physical reality, but studies of its back-reaction on the dynamics of spacetime are practically non-existent…

General Relativity and Quantum Cosmology · Physics 2018-02-08 Raúl Carballo-Rubio

We present several numerical solutions to a generalized Grad-Shafranov equation (GGSE), which governs axisymmetric plasma equilibria with incompressible flows of arbitrary direction, using fully connected, feed-forward, deep neural…

Plasma Physics · Physics 2022-03-24 D. A. Kaltsas , G. N. Throumoulopoulos

The standard equilibrium equation for magnetized plasma is extended to account for the magnetic polarization force. A factor of the pressure gradient arising from the magnetic decomposition of the Hall term survives the limit of vanishing…

Plasma Physics · Physics 2011-04-29 Robert W. Johnson

Curvilinear coordinate systems distinct from the rectangular Cartesian coordinate system are particularly valuable in the field calculations as they facilitate the expression of boundary conditions of differential equations in a reasonably…

Mathematical Physics · Physics 2024-05-16 Pavel Strunz

We investigate the morphology of a toroidal fluid membrane vesicle confined inside a spherical container. The equilibrium shapes are assembled in a geometrical phase diagram as a function of scaled area and reduced volume of the membrane.…

Biological Physics · Physics 2015-10-21 Lila Bouzar , Ferhat Menas , Martin Michael Müller

The self-similar equilibrium models of self-gravitating, rotating, isothermal systems are investigated analytically. In these models the rotation velocity is constant and the density varies as $\frac{f(\theta, \phi)}{r^2}$, where $r$ and…

Astrophysics · Physics 2009-11-06 Mohsen Shadmehri , Jamshid Ghanbari

This paper analyzes the relationship between the Single Helical relaxed states studied in R. Paccagnella, Phys. of Plasmas 23 (2016) 092512 and the so called 'helical ohmic equilibria', i.e. plasma states that are solutions of the helical…

Plasma Physics · Physics 2018-03-14 Roberto Paccagnella

Classical solutions of the spherically symmetric Nordstr\"{o}m-Vlasov system are shown to exist globally in time. The main motivation for investigating the mathematical properties of the Nordstr\"{o}m-Vlasov system is its relation to the…

General Relativity and Quantum Cosmology · Physics 2016-08-16 Håkan Andréasson , Simone Calogero , Gerhard Rein

We investigate in this paper the static radial coordinate-dependent spherically symmetric spacetime in teleparallel $F(T)$ gravity for a scalar field source. We begin by setting the static field equations (FEs) to be solved and solve the…

General Relativity and Quantum Cosmology · Physics 2025-03-20 Alexandre Landry

Stationary and axisymmetric solutions of relativistic rotating stars with strong mixed poloidal and toroidal magnetic fields are obtained numerically. Because of the mixed components of the magnetic field, the underlying stationary and…

High Energy Astrophysical Phenomena · Physics 2014-11-13 Koji Uryu , Eric Gourgoulhon , Charalampos Markakis , Kotaro Fujisawa , Antonios Tsokaros , Yoshiharu Eriguchi

Orthogonal coordinate systems enable expressing the boundary conditions of differential equations in accord with the physical boundaries of the problem. It can significantly simplify calculations. The orthogonal similar oblate spheroidal…

Classical Physics · Physics 2025-03-19 Pavel Strunz

Smooth axially symmetric Helfrich topological spheres are either round or else they must satisfy a second order equation known as the reduced membrane equation [17]. In this paper, we show that, conversely, axially symmetric closed genus…

Differential Geometry · Mathematics 2026-02-06 Rafael López , Bennett Palmer , Álvaro Pámpano

Analytical solutions to the wave equation in spheroidal coordinates in the short wavelength limit are considered. The asymptotic solutions for the radial function are significantly simplified, allowing scalar spheroidal wave functions to be…

Optics · Physics 2009-10-07 Martin Zeppenfeld

The kinetic description of relativistic plasmas in the presence of time-varying and spatially non-uniform electromagnetic fields is a fundamental theoretical issue both in astrophysics and plasma physics. This refers, in particular, to the…

High Energy Astrophysical Phenomena · Physics 2023-06-21 Claudio Cremaschini , Massimo Tessarotto , Zdeněk Stuchlík

We derive spherically symmetric solutions of the classical \lambda-R model, a minimal, anisotropic modification of general relativity with a preferred foliation and two local degrees of freedom. Starting from a 3 + 1 decomposition of the…

General Relativity and Quantum Cosmology · Physics 2017-08-30 Renate Loll , Luis Pires

We find exact solutions for f (T) teleparallel gravity for the cases of spherically and cylindrically symmetric tetrads. The adopted method is based on the search for Noether symmetries of point-like Lagrangians defined in Jordan and…

General Relativity and Quantum Cosmology · Physics 2020-03-18 Ali Nur Nurbaki , Salvatore Capozziello , Cemsinan Deliduman