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Magnetohydrodynamic (MHD) wave activity is ubiquitous in the solar atmosphere. MHD seismology aims to determine difficult to measure physical parameters in solar atmospheric magnetic and plasma structures by a combination of observed and…

Solar and Stellar Astrophysics · Physics 2015-06-04 Inigo Arregui

The role of the different helical components of the magnetic and velocity fields in the inverse spectral transfer of magnetic helicity is investigated through Fourier shell-to-shell transfer analysis. Both magnetic helicity and energetic…

Plasma Physics · Physics 2021-07-07 Jean-Mathieu Teissier , Wolf-Christian Müller

Consider an exterior problem of the three-dimensional elastic wave equation, which models the scattering of a time-harmonic plane wave by a rigid obstacle. The scattering problem is reformulated into a boundary value problem by introducing…

Analysis of PDEs · Mathematics 2017-09-07 Peijun Li , Xiaokai Yuan

We derive a steady-state, electromagnetic solution for collisional plasma and apply it to computing the total conductance for a vertically stratified ionosphere interrogated by a 3D signal with finite transverse wavelength, which we compare…

Plasma Physics · Physics 2022-11-22 Russell B. Cosgrove

This paper is concerned with reconstruction issue of some typical inverse problems and consists of three parts. First a framework of the enclosure method for an inverse source problem governed by the Helmholtz equation at a fixed wave…

Analysis of PDEs · Mathematics 2021-11-12 Masaru Ikehata

In this paper, we consider the three dimensional Vlasov equation with an inhomogeneous, varying direction, strong magnetic field. Whenever the magnetic field has constant intensity, the oscillations generated by the stiff term are periodic.…

Numerical Analysis · Mathematics 2019-07-11 Philippe Chartier , Nicolas Crouseilles , Mohammed Lemou , Florian Mehats , Xiaofei Zhao

Magnetic reconnection in an antiparallel uniform Harris current sheet equilibrium, which is initially perturbed by a region of enhanced resistivity limited in all three dimensions, is investigated through compressible magnetohydrodynamic…

Astrophysics · Physics 2009-10-31 Joerg Schumacher , Bernhard Kliem , Norbert Seehafer

We study the inverse problem of recovering a spatially dependent variable order in a time-fractional diffusion model from the boundary flux measurement generated by a single boundary excitation. It arises in the identification of…

Analysis of PDEs · Mathematics 2026-02-27 Jiho Hong , Bangti Jin , Yavar Kian

We present a numerical and analytical study of incompressible homogeneous conducting fluids using a helical Fourier representation. We analytically study both small- and large-scale dynamo properties, as well as the inverse cascade of…

Fluid Dynamics · Physics 2017-03-02 Moritz Linkmann , Ganapati Sahoo , Mairi McKay , Arjun Berera , Luca Biferale

We consider a linearised inverse conductivity problem for electromagnetic waves in a three dimensional bounded domain at a high time-harmonic frequency. Increasing stability bounds for the conductivity coefficient in the full Maxwell system…

Analysis of PDEs · Mathematics 2022-02-09 Victor Isakov , Shuai Lu , Boxi Xu

We consider a coefficient inverse problem for the dielectric permittivity in Maxwell's equations, with data consisting of boundary measurements of one or two backscattered or transmitted waves. The problem is treated using a Lagrangian…

Numerical Analysis · Mathematics 2016-03-18 John Bondestam Malmberg , Larisa Beilina

This paper proposes a new mathematical formulation for flow measurement based on the inverse source problem for wave equations with partial boundary measurement. Inspired by the design of acoustic Doppler current profilers (ADCPs), we…

Optimization and Control · Mathematics 2025-03-19 Jiwei Li , Lingyun Qiu , Zhongjing Wang , Hui Yu

We consider the inverse problem of reconstructing inhomogeneities by performing a finite number of scattering measurements of acoustic type in the time-harmonic setting. We set up the reconstruction as a fully discrete variational problem…

Analysis of PDEs · Mathematics 2026-02-24 Daniela Di Donato , Luca Rondi

This paper aims to numerically verify the large Reynolds number asymptotic theory of magneto-hydrodynamic (MHD) flows proposed in the companion paper Deguchi (2019). To avoid any complexity associated with the chaotic nature of turbulence…

Fluid Dynamics · Physics 2019-09-04 Kengo Deguchi

We present calculations that reconstruct electronic current densities in two stacked layers at known depths, using magnetic field data. Solving this inverse problem requires knowledge of the magnetic field in two planes -- one above both…

We analyze the anisotropy of turbulence in an electrically conducting fluid in the presence of a uniform magnetic field, for low magnetic Reynolds number, using the quasi-static approximation. In the linear limit, the kinetic energy of…

Fluid Dynamics · Physics 2011-04-01 Benjamin F. N. Favier , Fabien S. Godeferd , Claude Cambon , Alexandre Delache

We present numerical simulations of driven magnetohydrodynamic (MHD) turbulence with weak/moderate imposed magnetic fields. The main goal is to clarify dynamics of magnetic field growth. We also investigate the effects of the imposed…

Astrophysics · Physics 2011-02-11 J. Cho , E. Vishniac , A. Beresnyak , A. Lazarian , D. Ryu

We consider an inverse boundary value problem for a model time-harmonic equation of acoustic tomography of moving fluid with variable current velocity, sound speed, density and absorption. In the present article it is assumed that at fixed…

Analysis of PDEs · Mathematics 2017-02-14 Alexey Agaltsov

The three-dimensional compressible magnetohydrodynamic (MHD) isentropic flow with zero magnetic diffusivity is studied. The vanishing magnetic diffusivity causes significant difficulties due to the loss of dissipation of the magnetic field.…

Analysis of PDEs · Mathematics 2011-08-30 Xiaoli Li , Ning Su , Dehua Wang

Magnetic reconnection with asymmetry in the outflow direction occurs in the Earth's magnetotail, coronal mass ejections, flux cancellation events, astrophysical disks, spheromak merging experiments, and elsewhere in nature and the…

Plasma Physics · Physics 2010-09-16 N. A. Murphy , C. R. Sovinec , P. A. Cassak