Magnetic reconnection, plasmoids and numerical resolution

Fuente: arXiv
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Auteurs principaux: Morillo, José María García, Alexakis, Alexandros
Format: Preprint
Publié: 2024
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author Morillo, José María García
Alexakis, Alexandros
author_facet Morillo, José María García
Alexakis, Alexandros
contents Explaining fast magnetic reconnection in electrically conducting plasmas has been a theoretical challenge in plasma physics since its first description by Eugene N. Parker. In the recent years the observed reconnection rate has been shown by numerical simulations to be explained by the plasmoid instability that appears in highly conductive plasmas. In this work we show that the plasmoid instability is very sensitive to the numerical resolution used. It is shown that well resolved runs display no plasmoid instability even at Lundquist number as large as $5\cdot10^5$ achieved at resolutions of $32\,768^2$ grid points. On the contrary in simulations that are under-resolved below a threshold, the plasmoid instability manifests itself with the formation of larger plasmoids the larger the under-resolving is. The present results thus question the description of the plasmoid instability as a mechanism for fast magnetic reconnection.
format Preprint
id arxiv_https___arxiv_org_abs_2406_08951
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Magnetic reconnection, plasmoids and numerical resolution
Morillo, José María García
Alexakis, Alexandros
Plasma Physics
Solar and Stellar Astrophysics
Fluid Dynamics
Explaining fast magnetic reconnection in electrically conducting plasmas has been a theoretical challenge in plasma physics since its first description by Eugene N. Parker. In the recent years the observed reconnection rate has been shown by numerical simulations to be explained by the plasmoid instability that appears in highly conductive plasmas. In this work we show that the plasmoid instability is very sensitive to the numerical resolution used. It is shown that well resolved runs display no plasmoid instability even at Lundquist number as large as $5\cdot10^5$ achieved at resolutions of $32\,768^2$ grid points. On the contrary in simulations that are under-resolved below a threshold, the plasmoid instability manifests itself with the formation of larger plasmoids the larger the under-resolving is. The present results thus question the description of the plasmoid instability as a mechanism for fast magnetic reconnection.
title Magnetic reconnection, plasmoids and numerical resolution
topic Plasma Physics
Solar and Stellar Astrophysics
Fluid Dynamics
url https://arxiv.org/abs/2406.08951