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In this study, we investigate preferences of dipolar magnetic structure from a seed magnetic field in the rapidly rotating spherical shell dynamo models. In this study, we set up a realistic model to show the effect of the Lorentz force in…

Geophysics · Physics 2018-06-15 Subhajit Kar

The standard classic special relativistic transformation of the electromagnetic (EM) field under proper Lorentz transformations is revisited. As to the pure Lorentz-boosts, popular treatments on EM transformation contemplate ideal…

Classical Physics · Physics 2021-09-06 Salil K Bedkihal , Rajeev K Pathak

By performing estimates on the integral of the absolute value of vorticity along a local vortex line segment, we establish a relatively sharp dynamic growth estimate of maximum vorticity under some assumptions on the local geometric…

Analysis of PDEs · Mathematics 2010-11-29 Thomas Y. Hou , Zuoqiang Shi

The Liouville equation with non-constant magnetic field is obtained as a limit in the Planck constant \hbar of the Heisenberg equation with the same magnetic field. The convergence is with respect to an appropriate semi-classical pseudo…

Analysis of PDEs · Mathematics 2023-03-24 Immanuel Ben Porat

This paper concerns a class of monotone eigenvalue problems with eigenvector nonlinearities (mNEPv). The mNEPv is encountered in applications such as the computation of joint numerical radius of matrices, best rank-one approximation of…

Numerical Analysis · Mathematics 2022-11-11 Zhaojun Bai , Ding Lu

We consider a classical test particle subject to electromagnetic and gravitational fields, described by a Lagrangian depending on the acceleration and on a fundamental length. We associate to the particle a moving local reference frame and…

High Energy Physics - Theory · Physics 2009-11-11 M. Toller

In this paper we present some basic uniqueness results for evolutive equations under density constraints. First, we develop a rigorous proof of a well-known result (among specialists) in the case where the spontaneous velocity field…

Analysis of PDEs · Mathematics 2017-04-19 Simone Di Marino , Alpár Richárd Mészáros

We consider a class of linear second order differential equations with damping and external force. We investigate the link between a uniform bound on the forcing term and the corresponding ultimate bound on the velocity of solutions, and we…

Analysis of PDEs · Mathematics 2020-03-27 Marina Ghisi , Chiara Giraudo , Massimo Gobbino , Alain Haraux

The self-force problem---which asks how self-interaction affects a body's motion---has been poorly studied for spacetime dimensions $d \neq 4$. We remedy this for all $d \geq 3$ by nonperturbatively constructing momenta such that forces and…

General Relativity and Quantum Cosmology · Physics 2018-08-01 Abraham I. Harte , Peter Taylor , Éanna É. Flanagan

Magneto-curvature stresses could deform magnetic field lines and this would give rise to back reaction and restoring magnetic stresses [Tsagas, PRL (2001)]. Barrow et al [PRD (2008)] have shown in Friedman universe the expansion to be slow…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-03 Garcia de Andrade

Whereas in a coordinate-dependent setting the Euler-Lagrange equations establish necessary conditions for solving variational problems in which both the integrands of functionals and the resulting paths are assumed to be sufficiently…

Optimization and Control · Mathematics 2022-11-15 Gregory S. Chirikjian

The magnetic field measured in the Madison Dynamo Experiment shows intermittent periods of growth when an axial magnetic field is applied. The geometry of the intermittent field is consistent with the fastest growing magnetic eigenmode…

Plasma Physics · Physics 2009-11-11 M. D. Nornberg , E. J. Spence , R. D. Kendrick , C. M. Jacobson , C. B. Forest

Mathematics demonstrates that an ideally evolving magnetic field has an exponentially increasing sensitivity to non-ideal effects for all but truly exceptional evolutions. On a time scale that depends only logarithmically on the magnitude…

Plasma Physics · Physics 2020-01-29 Allen H. Boozer

Explicit expressions of the 3D velocity field in terms of the conserved quantities of ideal fluid thermocline theory, namely Bernoulli function, density, and potential vorticity, are generalised here to a compressible ocean with a realistic…

Fluid Dynamics · Physics 2023-03-07 Remi Tailleux

Kinematic dynamo in incompressible isotropic turbulent flows with high magnetic Prandtl number is considered. The approach interpreting an arbitrary magnetic field distribution as a superposition of localized perturbations (blobs) is…

Fluid Dynamics · Physics 2023-10-26 A. S. Il'yn , A. V. Kopyev , V. A. Sirota , K. P. Zybin

We consider the mixing behaviour of the solutions of the continuity equation associated with a divergence-free velocity field. In this announcement we sketch two explicit examples of exponential decay of the mixing scale of the solution, in…

Analysis of PDEs · Mathematics 2014-09-22 Giovanni Alberti , Gianluca Crippa , Anna L. Mazzucato

We consider the surface Stokes equation with Lagrange multiplier and approach it numerically. Using a Taylor-Hood surface finite element method, along with an appropriate estimate for the additional Lagrange multiplier, we derive a new…

Numerical Analysis · Mathematics 2025-07-03 Charles M. Elliott , Achilleas Mavrakis

The problem of solving perturbatively the equations describing the evolution of self-gravitating collisionless matter in an expanding universe considerably simplifies when directly formulated in terms of the gravitational and velocity…

Astrophysics · Physics 2015-06-24 Paolo Catelan , Francesco Lucchin , Sabino Matarrese , Lauro Moscardini

In order to generate a desired Kelvin (magnetic) force in a target subdomain moving along a prescribed trajectory, we propose a minimization problem with a tracking type cost functional. We use the so-called dipole approximation to realize…

Optimization and Control · Mathematics 2016-12-26 Harbir Antil , Ricardo H. Nochetto , Pablo Venegas

Lorentz invariant scalar functions of the magnetic field are defined in an ideal relativistic plasma. These invariants are advected by the plasma fluid motion and play the role of the {\it potential magnetic field} introduced by R. Hide in…

Plasma Physics · Physics 2018-09-12 Francesco Pegoraro
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