Wave interference from beats between nearly degenerate MRI eigenfrequencies drives cyclic large-scale dynamos in unstratified accretion disks via an oscillating shear-current effect, predicting a period of ~30(1+a²)^{1/2} orbital times.
Astrophysical magnetic fields and nonlinear dynamo theory
13 Pith papers cite this work. Polarity classification is still indexing.
13
Pith papers citing it
abstract
The current understanding of astrophysical magnetic fields is reviewed, focusing on their generation and maintenance by turbulence. In the astrophysical context this generation is usually explained by a self-excited dynamo, which involves flows that can amplify a weak 'seed' magnetic field exponentially fast. Particular emphasis is placed on the nonlinear saturation of the dynamo. Analytic and numerical results are discussed both for small scale dynamos, which are completely isotropic, and for large scale dynamos, where some form of parity breaking is crucial. Central to the discussion of large scale dynamos is the so-called alpha effect which explains the generation of a mean field if the turbulence lacks mirror symmetry, i.e. if the flow has kinetic helicity. Large scale dynamos produce small scale helical fields as a waste product that quench the large scale dynamo and hence the alpha effect. With this in mind, the microscopic theory of the alpha effect is revisited in full detail and recent results for the loss of helical magnetic fields are reviewed.
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A Runge-Kutta-Gegenbauer super-time-stepping method for stable, efficient handling of anisotropic non-ideal MHD diffusion.
An analytic energy spectrum for magnetic fields from electroweak symmetry breaking is obtained from random inhomogeneous Higgs configurations and validated with continuous-field simulations.
Efficient cosmic-ray transport in CR-pressure-dominated CGM simulations produces stronger cool-gas absorption (MgII, SiII) and covering fractions matching star-forming galaxies, while slow transport underproduces them.
High-resolution GR neutrino-radiation MHD simulation of 1.35-1.35 Msun BNS merger shows KHI-driven B-field amplification to magnetar levels (~10^50 erg, factor >=316) in 3 ms post-merger.
A self-consistent Parker bound, anchored in the dynamo seed eigenmode and including turbulent pre-acceleration of monopoles, relaxes the standard extended Parker bound by roughly two orders of magnitude at low and intermediate monopole masses.
UVIT FUV catalogues of ELAIS N1 plus CIGALE SED fits show SFR increasing with redshift and a flat young-to-total stellar mass ratio to z≲0.76, consistent with secular SFMS evolution.
A symbiotic axion-dilaton system sources a moderately chiral dark U(1) magnetic field of astrophysically relevant strength during radiation domination through tachyonic amplification without fine-tuning.
MHD simulations indicate that SKA-Mid Band 5a can detect filamentary polarized emission from ICM magnetic fields at high resolution and sensitivity, allowing inference of turbulence driving scales.
Proposes SKA surveys for a census of galactic magnetic fields from low to high redshift using polarimetry, RM grids, and lensed quasars to constrain dynamo models.
A review chapter summarizing theoretical 21-cm signatures from Cosmic Dawn and Reionization and their detectability with SKA-Low.
FRBs serve as cosmological probes via dispersion measure, scattering, and Faraday rotation to constrain baryon distribution, expansion history, magnetic fields, and fundamental physics effects.
Literature review summarizing observations, theoretical models, and MHD simulations of the small-scale solar dynamo operating in the solar photosphere and convection zone.
citing papers explorer
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Wave interference as the origin of the cyclic magnetorotational dynamo in accretion disks: insights from weakly nonlinear theory and local shearing box simulations
Wave interference from beats between nearly degenerate MRI eigenfrequencies drives cyclic large-scale dynamos in unstratified accretion disks via an oscillating shear-current effect, predicting a period of ~30(1+a²)^{1/2} orbital times.
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A robust super-time-stepping scheme for Ohmic and ambipolar diffusion
A Runge-Kutta-Gegenbauer super-time-stepping method for stable, efficient handling of anisotropic non-ideal MHD diffusion.
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Energy spectrum of magnetic fields from electroweak symmetry breaking
An analytic energy spectrum for magnetic fields from electroweak symmetry breaking is obtained from random inhomogeneous Higgs configurations and validated with continuous-field simulations.
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CRexit observed: probing cosmic ray transport in the circumgalactic medium with absorption line spectra
Efficient cosmic-ray transport in CR-pressure-dominated CGM simulations produces stronger cool-gas absorption (MgII, SiII) and covering fractions matching star-forming galaxies, while slow transport underproduces them.
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A magnetar formation in binary neutron star merger
High-resolution GR neutrino-radiation MHD simulation of 1.35-1.35 Msun BNS merger shows KHI-driven B-field amplification to magnetar levels (~10^50 erg, factor >=316) in 3 ms post-merger.
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Self-Consistent Parker Bound on Magnetic Monopoles
A self-consistent Parker bound, anchored in the dynamo seed eigenmode and including turbulent pre-acceleration of monopoles, relaxes the standard extended Parker bound by roughly two orders of magnitude at low and intermediate monopole masses.
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Deep far-UV observations of the ELAIS N1 field using AstroSat: Source catalogue, spectral energy distribution modelling and star formation
UVIT FUV catalogues of ELAIS N1 plus CIGALE SED fits show SFR increasing with redshift and a flat young-to-total stellar mass ratio to z≲0.76, consistent with secular SFMS evolution.
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Symbiotic Magnetogenesis during Radiation Domination
A symbiotic axion-dilaton system sources a moderately chiral dark U(1) magnetic field of astrophysically relevant strength during radiation domination through tachyonic amplification without fine-tuning.
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Unraveling the Imprints of Fluctuation-dynamo on the Intracluster Medium with the SKA
MHD simulations indicate that SKA-Mid Band 5a can detect filamentary polarized emission from ICM magnetic fields at high resolution and sensitivity, allowing inference of turbulence driving scales.
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Probing Magnetic Fields In and Around Galaxies Near and Far
Proposes SKA surveys for a census of galactic magnetic fields from low to high redshift using polarimetry, RM grids, and lensed quasars to constrain dynamo models.
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High-Redshift Signatures from the Cosmic Dawn and the Epoch of Reionization
A review chapter summarizing theoretical 21-cm signatures from Cosmic Dawn and Reionization and their detectability with SKA-Low.
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Fast Radio Bursts as Cosmological Probes
FRBs serve as cosmological probes via dispersion measure, scattering, and Faraday rotation to constrain baryon distribution, expansion history, magnetic fields, and fundamental physics effects.
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Research Progress on Solar Small-Scale Dynamo
Literature review summarizing observations, theoretical models, and MHD simulations of the small-scale solar dynamo operating in the solar photosphere and convection zone.