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Numerical simulation of the three-dimensional structure and dynamics of the non-magnetic solar chromosphere

Wedemeyer, S.; Freytag, B.; Steffen, M.; Ludwig, Hans-Günter LU and Holweger, H. (2004) In Astronomy & Astrophysics 414(3). p.1121-1137
Abstract
Three-dimensional numerical simulations with CO<SUP>5</SUP>, a newradiation hydrodynamics code, result in a dynamic, thermally bifurcatedmodel of the non-magnetic chromosphere of the quiet Sun. The 3D modelincludes the middle and low chromosphere, the photosphere, and the topof the convection zone, where acoustic waves are excited by convectivemotions. While the waves propagate upwards, they steepen into shocks,dissipate, and deposit their mechanienergy as heat in the chromosphere.Our numerical simulations show for the first time a complex 3D structureof the chromospheric layers, formed by the interaction of shock waves.Horizontal temperature cross-sections of the model chromosphere exhibita network of hot filaments and... (More)
Three-dimensional numerical simulations with CO<SUP>5</SUP>, a newradiation hydrodynamics code, result in a dynamic, thermally bifurcatedmodel of the non-magnetic chromosphere of the quiet Sun. The 3D modelincludes the middle and low chromosphere, the photosphere, and the topof the convection zone, where acoustic waves are excited by convectivemotions. While the waves propagate upwards, they steepen into shocks,dissipate, and deposit their mechanienergy as heat in the chromosphere.Our numerical simulations show for the first time a complex 3D structureof the chromospheric layers, formed by the interaction of shock waves.Horizontal temperature cross-sections of the model chromosphere exhibita network of hot filaments and enclosed cool regions. The horizontalpattern evolves on short time-scales of the order of typically 20-25 s,and has spatial scales comparable to those of the underlyinggranulation. The resulting thermal bifurcation, i.e., the co-existenceof cold and hot regions, provides temperatures high enough to producethe observed chromospheric UV emission and - at the same time -temperatures cold enough to allow the formation of molecules (e.g.,carbon monoxide). Our 3D model corroborates the finding bycitet{carlsson94} that the chromospheric temperature rise ofsemi-empirical models does not necessarily imply an increase in theaverage gas temperature but can be explained by the presence ofsubstantial spatial and temporal temperature inhomogeneities. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Sun: chromosphere, hydrodynamics, radiative transfer
in
Astronomy & Astrophysics
volume
414
issue
3
pages
1121 - 1137
publisher
EDP Sciences
external identifiers
  • wos:000189377200036
  • scopus:1042300861
ISSN
0004-6361
DOI
10.1051/0004-6361:20031682
language
English
LU publication?
yes
id
e5a4c01c-f597-4cbd-b718-99321ee301c5 (old id 129638)
date added to LUP
2007-07-20 14:37:23
date last changed
2017-11-19 04:14:39
@article{e5a4c01c-f597-4cbd-b718-99321ee301c5,
  abstract     = {Three-dimensional numerical simulations with CO&lt;SUP&gt;5&lt;/SUP&gt;, a newradiation hydrodynamics code, result in a dynamic, thermally bifurcatedmodel of the non-magnetic chromosphere of the quiet Sun. The 3D modelincludes the middle and low chromosphere, the photosphere, and the topof the convection zone, where acoustic waves are excited by convectivemotions. While the waves propagate upwards, they steepen into shocks,dissipate, and deposit their mechanienergy as heat in the chromosphere.Our numerical simulations show for the first time a complex 3D structureof the chromospheric layers, formed by the interaction of shock waves.Horizontal temperature cross-sections of the model chromosphere exhibita network of hot filaments and enclosed cool regions. The horizontalpattern evolves on short time-scales of the order of typically 20-25 s,and has spatial scales comparable to those of the underlyinggranulation. The resulting thermal bifurcation, i.e., the co-existenceof cold and hot regions, provides temperatures high enough to producethe observed chromospheric UV emission and - at the same time -temperatures cold enough to allow the formation of molecules (e.g.,carbon monoxide). Our 3D model corroborates the finding bycitet{carlsson94} that the chromospheric temperature rise ofsemi-empirical models does not necessarily imply an increase in theaverage gas temperature but can be explained by the presence ofsubstantial spatial and temporal temperature inhomogeneities.},
  author       = {Wedemeyer, S. and Freytag, B. and Steffen, M. and Ludwig, Hans-Günter and Holweger, H.},
  issn         = {0004-6361},
  keyword      = {Sun: chromosphere,hydrodynamics,radiative transfer},
  language     = {eng},
  number       = {3},
  pages        = {1121--1137},
  publisher    = {EDP Sciences},
  series       = {Astronomy & Astrophysics},
  title        = {Numerical simulation of the three-dimensional structure and dynamics of the non-magnetic solar chromosphere},
  url          = {http://dx.doi.org/10.1051/0004-6361:20031682},
  volume       = {414},
  year         = {2004},
}