Ambipolar diffusion in the Bifrost code
Ambipolar diffusion in the Bifrost code
复制标题
Bifrost 代码中的双极扩散
DOI：
10.1051/0004-6361/202037809
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发表时间：
2020
影响因子：
6.5
通讯作者：
Carlsson, M.
中科院分区：
文献类型：
--
作者：
Nóbrega-Siverio, D.;Martínez-Sykora, J.;Moreno-Insertis, F.;Carlsson, M.
ContextAmbipolar diffusion is a physical mechanism related to the drift between charged and neutral particles in a partially ionized plasma that is key to many different astrophysical systems. However, understanding its effects is challenging due to basic uncertainties concerning relevant microphysical aspects and the strong constraints it imposes on the numerical modeling.AimsOur aim is to introduce a numerical tool that allows us to address complex problems involving ambipolar diffusion in which, additionally, departures from ionization equilibrium are important or high resolution is needed. The primary application of this tool is for solar atmosphere calculations, but the methods and results presented here may also have a potential impact on other astrophysical systems.MethodsWe have developed a new module for the stellar atmosphere Bifrost code that improves its computational capabilities of the ambipolar diffusion term in the generalized Ohm’s law. This module includes, among other things, collision terms adequate to processes in the coolest regions in the solar chromosphere. As the main feature of the module, we have implemented the super time stepping (STS) technique, which allows an important acceleration of the calculations. We have also introduced hyperdiffusion terms to guarantee the stability of the code.ResultsWe show that to have an accurate value for the ambipolar diffusion coefficient in the solar atmosphere it is necessary to include as atomic elements in the equation of state not only hydrogen and helium, but also the main electron donors like sodium, silicon, and potassium. In addition, we establish a range of criteria to set up an automatic selection of the free parameters of the STS method that guarantees the best performance, optimizing the stability and speed for the ambipolar diffusion calculations. We validate the STS implementation by comparison with a self-similar analytical solution.
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DOI：
10.1086/161144
发表时间：
1983
期刊：
The Astrophysical Journal
影响因子：
--
作者：
E. Zweibel;K. Josafatsson
通讯作者：
K. Josafatsson
DOI：
10.1111/j.1365-2966.2007.11429.x
发表时间：
2006
影响因子：
4.8
作者：
Stephen O'Sullivan;Turlough P. Downes
通讯作者：
Turlough P. Downes
DOI：
10.1086/154304
发表时间：
1976
期刊：
The Astrophysical Journal
影响因子：
--
作者：
R. Klein;W. Kalkofen;R. Stein
通讯作者：
R. Stein
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DOI：
10.1088/0067-0049/181/2/413
发表时间：
2008
期刊：
The Astrophysical Journal Supplement Series
影响因子：
--
作者：
Eunwoo Choi;Jongsoo Kim;P. Wiita
通讯作者：
P. Wiita
关于安静的太阳色球层的最低温度
影响因子：
6.5
作者：
J. Leenaarts;M. Carlsson;V. Hansteen;B. Gudiksen
通讯作者：
B. Gudiksen