Paradigmatic flow for small-scale magnetohydrodynamics: Properties of the ideal case and the collision of current sheets

We propose two sets of initial conditions for magnetohydrodynamics (MHD) in which both the velocity and the magnetic fields have spatial symmetries that are preserved by the dynamical equations as the system evolves. When implemented numerically they allow for substantial savings in CPU time and mem...

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Autor principal: Mininni, Pablo Daniel
Publicado: 2008
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Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15393755_v78_n6_p_Lee
http://hdl.handle.net/20.500.12110/paper_15393755_v78_n6_p_Lee
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spelling paper:paper_15393755_v78_n6_p_Lee2023-06-08T16:20:38Z Paradigmatic flow for small-scale magnetohydrodynamics: Properties of the ideal case and the collision of current sheets Mininni, Pablo Daniel Data storage equipment Fluid dynamics Hydrodynamics Magnetic field effects Magnetic field measurement Magnetic fields Magnetic materials Solar energy Solar wind Wind power Basic properties Cpu times Current sheets Dynamical equations Energy spectrums Exponential decays Fast rotations Grid points Grid resolutions Initial conditions Logarithmic decrements Magnetic pressures Memory storages Near collisions Regular flows Scale separations Spatial resolutions Spatial symmetries Temporal evolutions Magnetohydrodynamics We propose two sets of initial conditions for magnetohydrodynamics (MHD) in which both the velocity and the magnetic fields have spatial symmetries that are preserved by the dynamical equations as the system evolves. When implemented numerically they allow for substantial savings in CPU time and memory storage requirements for a given resolved scale separation. Basic properties of these Taylor-Green flows generalized to MHD are given, and the ideal nondissipative case is studied up to the equivalent of 20483 grid points for one of these flows. The temporal evolution of the logarithmic decrements δ of the energy spectrum remains exponential at the highest spatial resolution considered, for which an acceleration is observed briefly before the grid resolution is reached. Up to the end of the exponential decay of δ, the behavior is consistent with a regular flow with no appearance of a singularity. The subsequent short acceleration in the formation of small magnetic scales can be associated with a near collision of two current sheets driven together by magnetic pressure. It leads to strong gradients with a fast rotation of the direction of the magnetic field, a feature also observed in the solar wind. © 2008 The American Physical Society. Fil:Mininni, P.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2008 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15393755_v78_n6_p_Lee http://hdl.handle.net/20.500.12110/paper_15393755_v78_n6_p_Lee
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Data storage equipment
Fluid dynamics
Hydrodynamics
Magnetic field effects
Magnetic field measurement
Magnetic fields
Magnetic materials
Solar energy
Solar wind
Wind power
Basic properties
Cpu times
Current sheets
Dynamical equations
Energy spectrums
Exponential decays
Fast rotations
Grid points
Grid resolutions
Initial conditions
Logarithmic decrements
Magnetic pressures
Memory storages
Near collisions
Regular flows
Scale separations
Spatial resolutions
Spatial symmetries
Temporal evolutions
Magnetohydrodynamics
spellingShingle Data storage equipment
Fluid dynamics
Hydrodynamics
Magnetic field effects
Magnetic field measurement
Magnetic fields
Magnetic materials
Solar energy
Solar wind
Wind power
Basic properties
Cpu times
Current sheets
Dynamical equations
Energy spectrums
Exponential decays
Fast rotations
Grid points
Grid resolutions
Initial conditions
Logarithmic decrements
Magnetic pressures
Memory storages
Near collisions
Regular flows
Scale separations
Spatial resolutions
Spatial symmetries
Temporal evolutions
Magnetohydrodynamics
Mininni, Pablo Daniel
Paradigmatic flow for small-scale magnetohydrodynamics: Properties of the ideal case and the collision of current sheets
topic_facet Data storage equipment
Fluid dynamics
Hydrodynamics
Magnetic field effects
Magnetic field measurement
Magnetic fields
Magnetic materials
Solar energy
Solar wind
Wind power
Basic properties
Cpu times
Current sheets
Dynamical equations
Energy spectrums
Exponential decays
Fast rotations
Grid points
Grid resolutions
Initial conditions
Logarithmic decrements
Magnetic pressures
Memory storages
Near collisions
Regular flows
Scale separations
Spatial resolutions
Spatial symmetries
Temporal evolutions
Magnetohydrodynamics
description We propose two sets of initial conditions for magnetohydrodynamics (MHD) in which both the velocity and the magnetic fields have spatial symmetries that are preserved by the dynamical equations as the system evolves. When implemented numerically they allow for substantial savings in CPU time and memory storage requirements for a given resolved scale separation. Basic properties of these Taylor-Green flows generalized to MHD are given, and the ideal nondissipative case is studied up to the equivalent of 20483 grid points for one of these flows. The temporal evolution of the logarithmic decrements δ of the energy spectrum remains exponential at the highest spatial resolution considered, for which an acceleration is observed briefly before the grid resolution is reached. Up to the end of the exponential decay of δ, the behavior is consistent with a regular flow with no appearance of a singularity. The subsequent short acceleration in the formation of small magnetic scales can be associated with a near collision of two current sheets driven together by magnetic pressure. It leads to strong gradients with a fast rotation of the direction of the magnetic field, a feature also observed in the solar wind. © 2008 The American Physical Society.
author Mininni, Pablo Daniel
author_facet Mininni, Pablo Daniel
author_sort Mininni, Pablo Daniel
title Paradigmatic flow for small-scale magnetohydrodynamics: Properties of the ideal case and the collision of current sheets
title_short Paradigmatic flow for small-scale magnetohydrodynamics: Properties of the ideal case and the collision of current sheets
title_full Paradigmatic flow for small-scale magnetohydrodynamics: Properties of the ideal case and the collision of current sheets
title_fullStr Paradigmatic flow for small-scale magnetohydrodynamics: Properties of the ideal case and the collision of current sheets
title_full_unstemmed Paradigmatic flow for small-scale magnetohydrodynamics: Properties of the ideal case and the collision of current sheets
title_sort paradigmatic flow for small-scale magnetohydrodynamics: properties of the ideal case and the collision of current sheets
publishDate 2008
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15393755_v78_n6_p_Lee
http://hdl.handle.net/20.500.12110/paper_15393755_v78_n6_p_Lee
work_keys_str_mv AT mininnipablodaniel paradigmaticflowforsmallscalemagnetohydrodynamicspropertiesoftheidealcaseandthecollisionofcurrentsheets
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