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Related papers: Parker's dynamo and geomagnetic reversals

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The profile of the differential rotation together with the sign of the alpha-effect determine the dynamo wave direction. In early models of the solar dynamo the dynamo wave often leads to a poleward migration of the activity belts. Flux…

Solar and Stellar Astrophysics · Physics 2020-09-30 Detlef Elstner , Yori Fournier , Rainer Arlt

The possibility is investigated that competition between fluctuations at different symmetry-related ordering wave vectors may affect the quantum phase transition between a fermi liquid and a longitudinal spin density wave state, in…

Strongly Correlated Electrons · Physics 2010-02-22 A. J. Millis

It is shown, that retardation in the $\alpha$-quenching in the Parker's dynamo model leads to parametric resonance. This result is observed in the numerical simulations and can be reproduced in the simple analytic model. The other…

Fluid Dynamics · Physics 2010-09-14 Maxim Reshetnyak

This is a review of recent work on quantum fluctuations of the electric field and of stress tensor operators and their physical effects. The probability distribution for vacuum fluctuations of the electric field is Gaussian, but that for…

High Energy Physics - Theory · Physics 2022-12-06 L. H. Ford

At kinetic scales in the solar wind, instabilities transfer energy from particles to fluctuations in the electromagnetic fields while restoring plasma conditions towards thermodynamic equilibrium. We investigate the interplay between…

Solar and Stellar Astrophysics · Physics 2023-04-05 Simon Opie , Daniel Verscharen , Christopher H. K. Chen , Christopher J. Owen , Philip A. Isenberg

Observations reveal nearly power-law spectra of magnetic and density plasma fluctuations at subproton scales in the solar wind, which indicates the presence of a turbulent cascade. We discuss the three-field and two-field models for…

Plasma Physics · Physics 2013-05-06 Stanislav Boldyrev , Jean Carlos Perez

The first results of the solar dynamo model that allows for the diamagnetic effect of inhomogeneous turbulence and the nonlocal alpha-effect due to the rise of magnetic loops are discussed. The nonlocal alpha-effect is not subject to the…

Solar and Stellar Astrophysics · Physics 2015-05-27 L. L. Kitchatinov , S. V. Olemskoy

We investigate the possibility that electromagnetic fluctuations are amplified in expanding universe by parametric resonance, during the oscillatory regime of a scalar field to which they are coupled. We consider scalar electrodynamics and…

Astrophysics · Physics 2016-11-03 F. Finelli

We use magnetoconductance fluctuation measurements of phase-coherent semiconductor billiards to quantify the contributions to the nonlinear electric conductance that are asymmetric under reversal of magnetic field. We experimentally…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 C. A. Marlow , R. P. Taylor , M. Fairbanks , I. Shorubalko , H. Linke

We study the possibility to reproduce the statistical relations of the sunspot activity cycle, like the so-called Waldmeier relations, the cycle period - amplitude and the cycle rise rate - amplitude relations, by means of the mean field…

Solar and Stellar Astrophysics · Physics 2015-05-30 V. V. Pipin , D. D. Sokoloff

In this paper we investigate the idea of Hanasz & Lesch 1993 that the galactic dynamo effect is due to the Parker instability of magnetic flux tubes. In addition to the former approach, we take into account more general physical conditions…

Astrophysics · Physics 2008-02-03 M. Hanasz , H. Lesch

Various possibilities are currently under discussion to explain the observed weakness of the intrinsic magnetic field of planet Mercury. One of the possible dynamo scenarios is a dynamo with feedback from the magnetosphere. Due to its weak…

Earth and Planetary Astrophysics · Physics 2015-05-18 D. Heyner , D. Schmitt , J. Wicht , K. -H. Glassmeier , H. Korth , U. Motschmann

Observations from Parker Solar Probe's first five orbits are used to investigate the helioradial evolution of probability density functions (PDFs) of fluctuations of magnetic field components, between \(\sim 28\) - 200 \(\rs\).…

Solar and Stellar Astrophysics · Physics 2022-11-09 Rohit Chhiber

This article presents a calculation of the mean electromotive force arising from general small-scale magnetohydrodynamical turbulence, within the framework of the second-order correlation approximation. With the goal of improving…

High Energy Astrophysical Phenomena · Physics 2015-11-23 Jonathan Squire , Amitava Bhattacharjee

A number of problems of solar and stellar dynamo theory are briefly reviewed and the current status of possible solutions is discussed. Results of direct numerical simulations are described in view of mean-field dynamo theory and the…

Astrophysics · Physics 2007-05-23 Axel Brandenburg

The intermittency of density fluctuations in the solar wind at kinetic scales has been examined using high time resolution Faraday cup measurements from the Spektr-R spacecraft. It was found that the probability density functions (PDFs) of…

Space Physics · Physics 2014-06-23 C. H. K. Chen , L. Sorriso-Valvo , J. Šafránková , Z. Němeček

We study the dynamics of magnetic fields in chiral magnetohydrodynamics, which takes into account the effects of an additional electric current related to the chiral magnetic effect in high energy plasmas. We perform direct numerical…

Plasma Physics · Physics 2022-02-15 Jennifer Schober , Igor Rogachevskii , Axel Brandenburg

Large-scale compressive slow-mode-like fluctuations can cause variations in the density, temperature, and magnetic-field magnitude in the solar wind. In addition, they also lead to fluctuations in the differential flow $U_{\rm p\alpha}$…

Space Physics · Physics 2023-08-07 Xingyu Zhu , Daniel Verscharen , Jiansen He , Bennett A. Maruca , Christopher J. Owen

We study the passive influence of quantum matter fluctuations on the expansion parameter of a congruence of timelike geodesics in a semiclassical regime. In particular, we show that, the perturbations of this parameter can be considered to…

Mathematical Physics · Physics 2016-08-08 Nicolò Drago , Nicola Pinamonti

Switchbacks are widely acknowledged phenomena observed by the Parker Solar Probe and appear to occur in patches. Previous studies focused on the fluctuations at the magnetic reversals. However, the nature of the fluctuations inside the…

Solar and Stellar Astrophysics · Physics 2021-04-27 Honghong Wu , Chuanyi Tu , Xin Wang , Liping Yang
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