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Newton-type solvers have been extensively employed for solving a variety of nonlinear system of algebraic equations. However, for some complex nonlinear system of algebraic equations, efficiently solving these systems remains a challenging…

Numerical Analysis · Mathematics 2025-01-08 Renjie Ding , Dongling Wang

The article examines a linear-quadratic Neumann control problem that is governed by a non-coercive elliptic equation. Due to the non-self-adjoint nature of the linear control-to-state operator, it is necessary to independently study both…

Optimization and Control · Mathematics 2025-06-25 Thomas Apel , Mariano Mateos , Arnd Rösch

We introduce a domain decomposition-based nonlinear preconditioned iteration for solving nonlinear, nonsmooth elliptic optimal control problems, with a nonlinear reaction term, $L^1$ regularization and box constraints on the control…

Optimization and Control · Mathematics 2021-04-02 Gabriele Ciaramella , Felix Kwok , Georg Müller

The magnetohydrodynamics (MHD) equations are continuum models used in the study of a wide range of plasma physics systems, including the evolution of complex plasma dynamics in tokamak disruptions. However, efficient numerical solution…

Computational Physics · Physics 2022-02-09 Qi Tang , Luis Chacon , Tzanio V. Kolev , John N. Shadid , Xian-Zhu Tang

An analytic solution to a generalized Grad-Shafranov equation with flow of arbitrary direction is obtained upon adopting the generic linearizing ansatz for the free functions related to the poloidal current, the static pressure and the…

Plasma Physics · Physics 2019-12-30 D. A. Kaltsas , A. Kuiroukidis , G. N. Throumoulopoulos

Force-free plasmas are a good approximation where the plasma pressure is tiny compared with the magnetic pressure, which is the case during the cold vertical displacement event (VDE) of a major disruption in a tokamak. On time scales long…

Plasma Physics · Physics 2023-03-27 Zakariae Jorti , Qi Tang , Konstantin Lipnikov , Xian-Zhu Tang

We study the dependence of some relevant tokamak equilibrium quantities on the toroidal plasma rotation. The Grad-Shafranov equation generalised to the rotating case is analytically solved employing two different representations for the…

Plasma Physics · Physics 2023-06-14 Matteo Del Prete , Giovanni Montani

Given a bounded domain $G \subset \R^d$, $d\geq 3$, we study smooth solutions of a linear parabolic equation with non-constant coefficients in $G$, which at the boundary have to $C^1$-match with some harmonic function in $\R^d \setminus…

Solar and Stellar Astrophysics · Physics 2012-12-14 Ralf Kaiser , Hannes Uecker

A theoretical model of the high-beta equilibrium of magnetospheric plasma was constructed by consistently connecting the (anisotropic pressure) Grad-Shafranov equation and the Vlasov equation. The Grad-Shafranov equation was used to…

Plasma Physics · Physics 2022-01-25 H. Aibara , Z. Yoshida , K. Shirahata

In this paper, we introduce a quasi-Newton method optimized for efficiently solving quasi-linear elliptic equations and systems, with a specific focus on GPU-based computation. By approximating the Jacobian matrix with a combination of…

Numerical Analysis · Mathematics 2025-03-25 Wenrui Hao , Sun Lee , Xiangxiong Zhang

The boundary problem about behavior (oscillations) of the electronic plasmas with arbitrary degree of degeneration of electronic gas in half-space with specular boundary conditions is analytically solved. The kinetic equation of…

Plasma Physics · Physics 2017-03-07 A. V. Latyshev , S. Sh. Suleymanova

We consider the free boundary problem for relativistic plasma--vacuum interfaces in two and three spatial dimensions. The plasma flow is governed by the equations of ideal relativistic magnetohydrodynamics, while the vacuum magnetic and…

Analysis of PDEs · Mathematics 2026-04-30 Paolo Secchi , Yuri Trakhinin , Tao Wang

In this paper we consider optimal control of nonlinear time-dependent fluid structure interactions. To determine a time-dependent control variable a BFGS algorithm is used, whereby gradient information is computed via a dual problem. To…

Optimization and Control · Mathematics 2020-08-11 L. Failer , T. Richter

We derive axisymmetric equilibrium equations in the context of the hybrid Vlasov model with kinetic ions and massless fluid electrons, assuming isothermal electrons and deformed Maxwellian distribution functions for the kinetic ions. The…

Plasma Physics · Physics 2024-06-06 D. A. Kaltsas , A. Kuiroukidis , P. J. Morrison , G. N. Throumoulopoulos

We consider the free boundary problem for a plasma--vacuum interface in ideal incompressible magnetohydrodynamics. Unlike the classical statement, where the vacuum magnetic field obeys the div-curl system of pre-Maxwell dynamics, we do not…

Analysis of PDEs · Mathematics 2022-02-17 Paolo Secchi , Yuan Yuan

We study the quasineutral limit for the relativistic Vlasov-Maxwell system in the framework of analytic regularity. Following the high regularity approach introduced by Grenier [44] for the Vlasov-Poisson system, we construct local-in-time…

Analysis of PDEs · Mathematics 2025-05-19 Antoine Gagnebin , Mikaela Iacobelli , Alexandre Rege , Stefano Rossi

We consider the free boundary problem for non-relativistic and relativistic ideal compressible magnetohydrodynamics in two and three spatial dimensions with the total pressure vanishing on the plasma--vacuum interface. We establish the…

Analysis of PDEs · Mathematics 2021-04-06 Yuri Trakhinin , Tao Wang

This work presents a novel version of recently developed Gauss-Newton method for solving systems of nonlinear equations, based on upper bound of solution residual and quadratic regularization ideas. We obtained for such method global…

Optimization and Control · Mathematics 2021-05-04 Nikita Yudin , Alexander Gasnikov

We consider the free boundary problem for the plasma-vacuum interface in ideal compressible magnetohydrodynamics (MHD). In the plasma region, the flow is governed by the usual compressible MHD equations, while in the vacuum region we…

Analysis of PDEs · Mathematics 2014-07-22 Davide Catania , Marcello D'Abbicco , Paolo Secchi

In this paper, we establish regularity and uniqueness results for Grad-Mercier type equations that arise in the context of plasma physics. We show that solutions of this problem naturally develop a dead core, which corresponds to the set…

Analysis of PDEs · Mathematics 2025-04-18 Luis Caffarelli , Antonio Farah , Daniel Restrepo