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Title: NUMERICAL SIMULATIONS OF CORONAL HEATING THROUGH FOOTPOINT BRAIDING

Abstract

Advanced three-dimensional (3D) radiative MHD simulations now reproduce many properties of the outer solar atmosphere. When including a domain from the convection zone into the corona, a hot chromosphere and corona are self-consistently maintained. Here we study two realistic models, with different simulated areas, magnetic field strength and topology, and numerical resolution. These are compared in order to characterize the heating in the 3D-MHD simulations which self-consistently maintains the structure of the atmosphere. We analyze the heating at both large and small scales and find that heating is episodic and highly structured in space, but occurs along loop-shaped structures, and moves along with the magnetic field. On large scales we find that the heating per particle is maximal near the transition region and that widely distributed opposite-polarity field in the photosphere leads to a greater heating scale height in the corona. On smaller scales, heating is concentrated in current sheets, the thicknesses of which are set by the numerical resolution. Some current sheets fragment in time, this process occurring more readily in the higher-resolution model leading to spatially highly intermittent heating. The large-scale heating structures are found to fade in less than about five minutes, while the smaller, local, heatingmore » shows timescales of the order of two minutes in one model and one minutes in the other, higher-resolution, model.« less

Authors:
; ;  [1];  [2]
  1. Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway)
  2. Physikalisch-Meteorologische Observatorium, PMOD/WRC, Dorfstrasse 33, 7260 Davos Dorf (Switzerland)
Publication Date:
OSTI Identifier:
22525344
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 811; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CHROMOSPHERE; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; CONVECTION; HEATING; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; PHOTOSPHERE; RESOLUTION; SCALE HEIGHT; SOLAR CORONA; SPACE; SUN

Citation Formats

Hansteen, V., Pontieu, B. De, Carlsson, M., and Guerreiro, N., E-mail: viggo.hansteen@astro.uio.no, E-mail: mats.carlsson@astro.uio.no, E-mail: nuno.guerreiro@pmodwrc.ch, E-mail: bdp@lmsal.com. NUMERICAL SIMULATIONS OF CORONAL HEATING THROUGH FOOTPOINT BRAIDING. United States: N. p., 2015. Web. doi:10.1088/0004-637X/811/2/106.
Hansteen, V., Pontieu, B. De, Carlsson, M., & Guerreiro, N., E-mail: viggo.hansteen@astro.uio.no, E-mail: mats.carlsson@astro.uio.no, E-mail: nuno.guerreiro@pmodwrc.ch, E-mail: bdp@lmsal.com. NUMERICAL SIMULATIONS OF CORONAL HEATING THROUGH FOOTPOINT BRAIDING. United States. doi:10.1088/0004-637X/811/2/106.
Hansteen, V., Pontieu, B. De, Carlsson, M., and Guerreiro, N., E-mail: viggo.hansteen@astro.uio.no, E-mail: mats.carlsson@astro.uio.no, E-mail: nuno.guerreiro@pmodwrc.ch, E-mail: bdp@lmsal.com. Thu . "NUMERICAL SIMULATIONS OF CORONAL HEATING THROUGH FOOTPOINT BRAIDING". United States. doi:10.1088/0004-637X/811/2/106.
@article{osti_22525344,
title = {NUMERICAL SIMULATIONS OF CORONAL HEATING THROUGH FOOTPOINT BRAIDING},
author = {Hansteen, V. and Pontieu, B. De and Carlsson, M. and Guerreiro, N., E-mail: viggo.hansteen@astro.uio.no, E-mail: mats.carlsson@astro.uio.no, E-mail: nuno.guerreiro@pmodwrc.ch, E-mail: bdp@lmsal.com},
abstractNote = {Advanced three-dimensional (3D) radiative MHD simulations now reproduce many properties of the outer solar atmosphere. When including a domain from the convection zone into the corona, a hot chromosphere and corona are self-consistently maintained. Here we study two realistic models, with different simulated areas, magnetic field strength and topology, and numerical resolution. These are compared in order to characterize the heating in the 3D-MHD simulations which self-consistently maintains the structure of the atmosphere. We analyze the heating at both large and small scales and find that heating is episodic and highly structured in space, but occurs along loop-shaped structures, and moves along with the magnetic field. On large scales we find that the heating per particle is maximal near the transition region and that widely distributed opposite-polarity field in the photosphere leads to a greater heating scale height in the corona. On smaller scales, heating is concentrated in current sheets, the thicknesses of which are set by the numerical resolution. Some current sheets fragment in time, this process occurring more readily in the higher-resolution model leading to spatially highly intermittent heating. The large-scale heating structures are found to fade in less than about five minutes, while the smaller, local, heating shows timescales of the order of two minutes in one model and one minutes in the other, higher-resolution, model.},
doi = {10.1088/0004-637X/811/2/106},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 811,
place = {United States},
year = {2015},
month = {10}
}