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We present theoretical models for the time-dependent voltage of an electrochemical cell in response to a current step, including effects of diffuse charge (or "space charge") near the electrodes on Faradaic reaction kinetics. The full model…

Chemical Physics · Physics 2015-05-14 M. van Soestbergen , P. M. Biesheuvel , M. Z. Bazant

The theory of the effect of external fluctuation force on the stability and spatial distribution of mutually interacting and slowly evaporating charged drops, levitated in an electrodynamic balance, is presented using classical…

Fluid Dynamics · Physics 2020-07-07 Mohit Singh , Y. S. Mayya , Rochish Thaokar

We have explored the magnetosphere described by a numerical solution for an axisymmetric rotating field satisfying the force-free and ideal MHD conditions everywhere. The electric current distribution is determined by the requirement of…

Astrophysics · Physics 2009-11-07 Jun Ogura , Yasufumi Kojima

Results from a numerical study of fluctuation dynamo in a collisionless, weakly magnetized plasma are presented. The key difference between this dynamo and its magnetohydrodynamic (MHD) counterpart is the adiabatic production of…

High Energy Astrophysical Phenomena · Physics 2018-08-17 Denis A. St-Onge , Matthew W. Kunz

In this work, the development of two-dimensional current sheets with respect to tearing-modes, in collisionless plasmas with a strong guide field, is analysed. During their non-linear evolution, these thin current sheets can become unstable…

Plasma Physics · Physics 2025-03-04 C. Granier , R. Numata , D. Borgogno , E. Tassi , D. Grasso

The particle-in-cell approach has proven effective at modeling neutron star and black hole magnetospheres from first principles, but global simulations are plagued with an unrealistically small separation between the scales where…

High Energy Astrophysical Phenomena · Physics 2024-10-09 Adrien Soudais , Benoît Cerutti , Ioannis Contopoulos

The combination of protrusions and retractions in the movement of polarized cells leads to understand the effect of possible synchronisation between the two ends of the cells. This synchronisation, in turn, could lead to different dynamics…

Cell Behavior · Quantitative Biology 2021-09-21 Gissell Estrada-Rodriguez , Benoit Perthame

We present the magnetic and electric field structures as well as the currents and charge densities of pulsar magnetospheres which do not obey the ideal condition, ${\bf E \cdot B =0}$. Since the acceleration of particles and the production…

Solar and Stellar Astrophysics · Physics 2015-05-30 Constantinos Kalapotharakos , Demosthenes Kazanas , Alice Harding , Ioannis Contopoulos

We investigate the three-dimensional structure of the pulsar magnetosphere through time-dependent numerical simulations of a magnetic dipole that is set in rotation. We developed our own Eulerian finite difference time domain numerical…

Astrophysics · Physics 2009-11-13 Constantinos Kalapotharakos , Ioannis Contopoulos

Contopoulos 2019 proposed that a dissipation zone develops in the magnetosphere of young pulsars at the edge of the closed-line region beyond the light cylinder. This is necessary in order to supply the charge carriers that will establish…

High Energy Astrophysical Phenomena · Physics 2019-05-29 Ioannis Contopoulos , Petros Stefanou

With the support of hybrid-kinetic simulations and analytic theory, we describe the nonlinear behaviour of long-wavelength non-propagating (NP) modes and fast magnetosonic waves in high-$\beta$ collisionless plasmas, with particular…

High Energy Astrophysical Phenomena · Physics 2023-04-05 Stephen Majeski , Matthew W. Kunz , Jonathan Squire

We study, by means of extensive direct numerical simulations, the turbulent flow produced by a two-dimensional cellular forcing in a cubic box with periodic boundary conditions. In spite of the strong anisotropy of the forcing, we find that…

Fluid Dynamics · Physics 2022-11-22 S. Berti , G. Boffetta , S. Musacchio

Rolling of a small sphere on a solid support is governed by a non-linear friction that is akin to the Coulombic dry fiction. No motion occurs when the external field is weaker than the frictional resistance. However, with the intervention…

Statistical Mechanics · Physics 2012-03-22 P. S. Goohpattader , M. K. Chaudhury

We investigate the evolution of a disk wind into a collimated jet under the influence of magnetic diffusivity, assuming that the turbulent pattern in the disk will also enter the disk corona and the jet. Using the ZEUS-3D code in the…

Astrophysics · Physics 2009-11-07 Christian Fendt , Miljenko Cemeljic

Many astrophysical bodies harbor magnetic fields that are thought to be sustained by a dynamo process. However, it has been argued that the production of large-scale magnetic fields by mean-field dynamo action is strongly suppressed at…

Astrophysics of Galaxies · Physics 2013-01-22 Fabio Del Sordo , Gustavo Guerrero , Axel Brandenburg

Starting with the most general form of Maxwell's macroscopic equations in which the free charge and free current densities, rho_free and J_free, as well as the densities of polarization and magnetization, P and M, are arbitrary functions of…

Optics · Physics 2012-08-07 Masud Mansuripur

Plasma in the terrestrial magnetosheath is characterised by very weak particle-particle collisions, so kinetic microinstabilities are thought to be responsible for regulating the thermodynamics of the plasma. By exciting electromagnetic…

The focus of this study is to understand the evolution of instability in centrifugal buoyancy-induced flow in a rotating system. The problem is of interest in atmospheric flows as well as in engineering applications. In this study, we…

Fluid Dynamics · Physics 2021-11-16 Deepak Saini , Richard D. Sandberg

We present detailed analysis of the turbulence observed in three-dimensional particle-in-cell simulations of magnetic reconnection at the magnetopause. The parameters are representative of an electron diffusion region encounter of the…

Space Physics · Physics 2018-05-04 L. Price , M. Swisdak , J. F. Drake , J. L. Burch , P. A. Cassak , R. E. Ergun

Following earlier work, reference is made to the classical entropic force which results from spatially variable disorder, an exclusively repulsive force. In terms of macroscopic variables it is applied to magnetohydrodynamics, causing minor…

Space Physics · Physics 2023-05-16 W. Baumjohann , R. A. Treumann