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Related papers: Inverse problem in Parker's dynamo

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We find general relativistic solutions of equilibrium magnetic field configurations in magnetars, extending previous results of Colaiuda et al. (2008). Our method is based on the solution of the relativistic Grad-Shafranov equation, to…

Solar and Stellar Astrophysics · Physics 2010-11-02 R. Ciolfi , V. Ferrari , L. Gualtieri , J. A. Pons

Estimating the trace of the inverse of a large matrix is an important problem in lattice quantum chromodynamics. A multilevel Monte Carlo method is proposed for this problem that uses different degree polynomials for the levels. The…

High Energy Physics - Lattice · Physics 2023-06-19 Paul Lashomb , Ronald B. Morgan , Travis Whyte , Walter Wilcox

We consider two inverse problems related to the tokamak \textsl{Tore Supra} through the study of the magnetostatic equation for the poloidal flux. The first one deals with the Cauchy issue of recovering in a two dimensional annular domain…

Analysis of PDEs · Mathematics 2012-04-09 Yannick Fischer , Benjamin Marteau , Yannick Privat

The irregular polarity reversals of the Earth's magnetic field have attracted much interest during the last decades. Despite the fact that recent numerical simulations of the geodynamo have shown nice polarity transitions, the very reason…

Geophysics · Physics 2007-05-23 F. Stefani , G. Gerbeth , U. Guenther

The solar steady emission in gamma rays is due to the interactions of Galactic cosmic rays with the solar atmosphere and with the low-energy solar photon field via inverse Compton scattering. The emission is sensitive to the magnetic field…

High Energy Physics - Phenomenology · Physics 2025-05-28 M. N. Mazziotta

We show that a model, recently used to describe all the dynamical regimes of the magnetic field generated by the dynamo effect in the VKS experiment [1], also provides a simple explanation of the reversals of Earth's magnetic field, despite…

Geophysics · Physics 2009-11-13 F. Petrelis , S. Fauve , E. Dormy , J. P. Valet

The inverse problem for a disordered system involves determining the interparticle interaction parameters consistent with a given set of experimental data. Recently, Rutledge has shown (Phys. Rev. E63, 021111 (2001)) that such problems can…

Statistical Mechanics · Physics 2009-11-10 N. B. Wilding

A number of applications require the computation of the trace of a matrix that is implicitly available through a function. A common example of a function is the inverse of a large, sparse matrix, which is the focus of this paper. When the…

Numerical Analysis · Computer Science 2016-09-07 Lingfei Wu , Jesse Laeuchli , Vassilis Kalantzis , Andreas Stathopoulos , Efstratios Gallopoulos

Existence of the magnetic monopole is compatible with the fundamental laws of nature, however, this illusive particle has yet to be detected experimentally. In this work, we show that an electric charge near the topological surface state…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Xiao-Liang Qi , Rundong Li , Jiadong Zang , Shou-Cheng Zhang

The magnetostatic field distribution in a nonlinear medium amounts to the unique minimizer of the magnetic coenergy over all fields that can be generated by the same current. This is a nonlinear saddlepoint problem whose numerical solution…

Numerical Analysis · Mathematics 2024-03-28 Herbert Egger , Felix Engertsberger , Klaus Roppert

This paper is concerned with an inverse moving point source problem in electromagnetics. The aim is to reconstruct the moving orbit from the tangential components of magnetic fields taken at a finite number of observation points. The…

Numerical Analysis · Mathematics 2025-07-22 Minghui Li , Guanghui Hu , Yue Zhao

The quantum Monte-Carlo method is applied to two-dimensional electron systems under strong magnetic fields. The negative-sign problem involved by this method can be avoided for certain filling factors by modifying interaction parameters…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Sei Suzuki , Tatsuya Nakajima

We attempt to get a polynomial solution to the inverse problem, that is, to determine the form of the mechanical Hamiltonian when given the energy spectrum and transition dipole moment matrix. Our approach is to determine the potential in…

Quantum Physics · Physics 2016-09-29 Nathan J. Dawson , Mark G. Kuzyk

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

We have used Monte Carlo simulations to investigate the magnetic properties of asymmetric dots as a function of their geometry. The asymmetry of round dots is produced by cutting off a fraction of the dot and is characterized by an…

Mesoscale and Nanoscale Physics · Physics 2011-06-08 N. M. Vargas , S. Allende , B. Leighton , J. Escrig , J. Mejía-López , D. Altbir , Ivan K. Schuller

The inverse problem which consists of determining the flow at the Earth's Core Mantle Boundary according to an outer core magnetic field and secular variation model, has been investigated through a Bayesian formalism. To circumvent the…

Geophysics · Physics 2015-06-17 Julien Baerenzung , Matthias Holschneider , Vincent Lesur

A particular instance of the inverse magnetisation problem is considered. It is assumed that the support of a magnetic sample (a source term in the Poisson equation in $\mathbb{R}^3$) is contained in a bounded planar set parallel to the…

Analysis of PDEs · Mathematics 2024-11-15 Dmitry Ponomarev

Helicity and \alpha effect driven by the nonaxisymmetric Tayler instability of toroidal magnetic fields in stellar radiation zones are computed. In the linear approximation a purely toroidal field always excites pairs of modes with…

Solar and Stellar Astrophysics · Physics 2015-05-28 G. Ruediger , L. L. Kitchatinov , D. Elstner

In this paper we develop theoretical analysis and numerical reconstruction techniques for the solution of an inverse boundary value problem dealing with the nonlinear, time-dependent monodomain equation, which models the evolution of the…

Analysis of PDEs · Mathematics 2017-01-27 Elena Beretta , Cecilia Cavaterra , Maria Cristina Cerutti , Andrea Manzoni , Luca Ratti

An oblique pulsar magnetosphere with a plasma conductivity is studied by using a pseudo-spectral method. In the pseudo-spectral method, the time-dependent Maxwell equations are solved, both electric and magnetic fields are expanded in terms…

High Energy Astrophysical Phenomena · Physics 2016-07-27 Gang Cao , Li Zhang , Sineng Sun