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Title: EFFECTS OF PENETRATIVE CONVECTION ON SOLAR DYNAMO

Abstract

Spherical solar dynamo simulations are performed. A self-consistent, fully compressible magnetohydrodynamic system with a stably stratified layer below the convective envelope is numerically solved with a newly developed simulation code based on the Yin-Yang grid. The effects of penetrative convection are studied by comparing two models with and without the stable layer. The differential rotation profile in both models is reasonably solar-like with equatorial acceleration. When considering the penetrative convection, a tachocline-like shear layer is developed and maintained beneath the convection zone without assuming any forcing. While the turbulent magnetic field becomes predominant in the region where the convective motion is vigorous, mean-field components are preferentially organized in the region where the convective motion is less vigorous. Particularly in the stable layer, the strong, large-scale field with a dipole symmetry is spontaneously built up. The polarity reversal of the mean-field component takes place globally and synchronously throughout the system regardless of the presence of the stable layer. Our results suggest that the stably stratified layer is a key component for organizing the large-scale strong magnetic field, but is not essential for the polarity reversal.

Authors:
; ;  [1]
  1. Department of Computational Science, Graduate School of System Informatics, Kobe University, Kobe (Japan)
Publication Date:
OSTI Identifier:
22270530
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 778; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; CONVECTION; DIPOLES; LAYERS; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; MEAN-FIELD THEORY; ROTATION; SPHERICAL CONFIGURATION; SUN

Citation Formats

Masada, Youhei, Yamada, Kohei, and Kageyama, Akira, E-mail: ymasada@harbor.kobe-u.ac.jp. EFFECTS OF PENETRATIVE CONVECTION ON SOLAR DYNAMO. United States: N. p., 2013. Web. doi:10.1088/0004-637X/778/1/11.
Masada, Youhei, Yamada, Kohei, & Kageyama, Akira, E-mail: ymasada@harbor.kobe-u.ac.jp. EFFECTS OF PENETRATIVE CONVECTION ON SOLAR DYNAMO. United States. doi:10.1088/0004-637X/778/1/11.
Masada, Youhei, Yamada, Kohei, and Kageyama, Akira, E-mail: ymasada@harbor.kobe-u.ac.jp. Wed . "EFFECTS OF PENETRATIVE CONVECTION ON SOLAR DYNAMO". United States. doi:10.1088/0004-637X/778/1/11.
@article{osti_22270530,
title = {EFFECTS OF PENETRATIVE CONVECTION ON SOLAR DYNAMO},
author = {Masada, Youhei and Yamada, Kohei and Kageyama, Akira, E-mail: ymasada@harbor.kobe-u.ac.jp},
abstractNote = {Spherical solar dynamo simulations are performed. A self-consistent, fully compressible magnetohydrodynamic system with a stably stratified layer below the convective envelope is numerically solved with a newly developed simulation code based on the Yin-Yang grid. The effects of penetrative convection are studied by comparing two models with and without the stable layer. The differential rotation profile in both models is reasonably solar-like with equatorial acceleration. When considering the penetrative convection, a tachocline-like shear layer is developed and maintained beneath the convection zone without assuming any forcing. While the turbulent magnetic field becomes predominant in the region where the convective motion is vigorous, mean-field components are preferentially organized in the region where the convective motion is less vigorous. Particularly in the stable layer, the strong, large-scale field with a dipole symmetry is spontaneously built up. The polarity reversal of the mean-field component takes place globally and synchronously throughout the system regardless of the presence of the stable layer. Our results suggest that the stably stratified layer is a key component for organizing the large-scale strong magnetic field, but is not essential for the polarity reversal.},
doi = {10.1088/0004-637X/778/1/11},
journal = {Astrophysical Journal},
number = 1,
volume = 778,
place = {United States},
year = {Wed Nov 20 00:00:00 EST 2013},
month = {Wed Nov 20 00:00:00 EST 2013}
}
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