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The dynamic formulation of optimal transport has attracted growing interests in scientific computing and machine learning, and its computation requires to solve a PDE-constrained optimization problem. The classical Eulerian discretization…

Machine Learning · Computer Science 2022-05-17 Wei Wan , Yuejin Zhang , Chenglong Bao , Bin Dong , Zuoqiang Shi

We generalize the Rigid-Field Hydrodynamic equations to accommodate arbitrary magnetic field topologies, resulting in a new Arbitrary Rigid-Field hydrodynamic (ARFHD) formalism. We undertake a critical point calculation of the steady-state…

Solar and Stellar Astrophysics · Physics 2016-08-01 Christopher Bard , Richard H. D. Townsend

A stationary self-consistent outflow of a magnetised relativistic plasma from a rotating object with an initially monopole-like magnetic field is investigated in the ideal MHD approximation under the condition $\sigma/U_0^2 >1$, where…

Astrophysics · Physics 2009-11-06 S. Bogovalov

We study the inverse problem of reconstructing an incompressible velocity field $\boldsymbol{v}$ from observations of the induced magnetic field $\boldsymbol{b}$. In the presence of a strong, constant background field $\mathbf{F}$, the…

Analysis of PDEs · Mathematics 2026-02-26 Yacine Mokhtari , Christina Frederick , Yunan Yang , Bjorn Engquist

For the two dimensional stationary MHD equations, we proved that Liouville type theorems hold if the velocity is growing at infinity, where the magnetic field is assumed to be bounded under a smallness condition. The key point is to…

Analysis of PDEs · Mathematics 2019-06-04 Wendong Wang

The velocity field within a steady toroidal vortex is found for arbitrary mean core radius and section ellipticity. The problem is solved by transforming to coordinates that define invariant sets. The method allows the properties of the…

Fluid Dynamics · Physics 2026-04-21 T. S. Morton

For the rigid, nonrotating motion of an extended charge in an arbitrary electromagnetic field, an equation of motion is derived by Lorentz-invariantly calculating the 4-Lorentz force = external 4-force + 4-self-force, acting upon the…

Mathematical Physics · Physics 2007-05-23 Helmut Stoeckel

We are investigating numerically the non-linear behavior of a space-periodic MHD system with ABC forcing. Most computations are performed for magnetic Reynolds numbers increasing from 0 to 60 and a fixed kinematic Reynolds number, small…

Fluid Dynamics · Physics 2007-05-23 Olga M. Podvigina

We investigate field-driven domain wall (DW) propagation in magnetic nanowires in the framework of the Landau-Lifshitz-Gilbert equation. We propose a new strategy to speed up the DW motion in a uniaxial magnetic nanowire by using an optimal…

Materials Science · Physics 2015-05-14 Z. Z. Sun , J. Schliemann

In this paper, we investigate Liouville type theorems for the 3D stationary magneto-micropolar fluid equations and micropolar fluid equations. Adopting an iteration procedure, taking advantage of the special structure of the equations and…

Analysis of PDEs · Mathematics 2026-05-12 Zhibing Zhang , Qian Zu

This paper presents a simple and systematic method to show how the potentials in the Lorentz, Coulomb, Kirchhoff, velocity and temporal gauges yield the same retarded electric and magnetic fields. The method appropriately uses the dynamical…

Classical Physics · Physics 2007-05-23 Jose A. Heras

One of the crucial features of optimal transport on Riemannian manifolds is the equivalence of the `static', original, formulation of the problem and of the `dynamic' one, based on the study of the continuity equation. This furnishes the…

Analysis of PDEs · Mathematics 2026-01-21 Nicola Gigli , Felix Rott , Matteo Zanardini

We derive the exact solution of the Boltzmann kinetic equation for the three-dimensional Lorentz model in the presence of a constant and uniform magnetic field. The velocity distribution of the electrons reduces exponentially fast to its…

Statistical Mechanics · Physics 2009-11-11 F. Cornu , J. Piasecki

We consider the generation of magnetic field by a turbulent flow. For the linear induction equation (i.e. the kinematic dynamo problem), we show that the statistical moments of the magnetic field display multiscaling and in particular…

Fluid Dynamics · Physics 2018-09-12 Kannabiran Seshasayanan , Francois Petrelis

Starting from the continuity equation for the magnetization in time-dependent spin-density functional theory, we derive an expression for the effective time-dependent magnetic fields driving the out-of-equilibrium spin dynamics in magnetic…

Mesoscale and Nanoscale Physics · Physics 2017-01-18 Jacopo Simoni , Maria Stamenova , Stefano Sanvito

This paper provides a rigorous convergence rate and complexity analysis for a recently introduced framework, called PDE acceleration, for solving problems in the calculus of variations, and explores applications to obstacle problems. PDE…

Numerical Analysis · Mathematics 2019-07-31 Jeff Calder , Anthony Yezzi

Magnetic fields are ubiquitous in the Universe. Extragalactic disks, halos and clusters have consistently been shown, via diffuse radio-synchrotron emission and Faraday rotation measurements, to exhibit magnetic field strengths ranging from…

We study the minimization of convex, variational integrals of linear growth among all functions in the Sobolev space $W^{1,1}$ with prescribed boundary values (or its equivalent formulation as a boundary value problem for a degenerately…

Analysis of PDEs · Mathematics 2019-10-08 Lisa Beck , Miroslav Bulíček , Erika Maringová

Electromagnetic field produced by magnetic multipoles in hyperbolic motion is derived and compared with electromagnetic field produced by electric multipoles in hyperbolic motion. The resulting fields are related by duality symmetry.…

General Relativity and Quantum Cosmology · Physics 2007-05-23 V. Pravda , A. Pravdova

We derive a Cartesian componentwise description of the covariant derivative of tangential tensor fields of any degree on general manifolds. This allows to reformulate any vector- and tensor-valued surface PDE in a form suitable to be solved…

Numerical Analysis · Mathematics 2019-05-01 Michael Nestler , Ingo Nitschke , Axel Voigt