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Title: MAGNETIC FIELD INTENSIFICATION BY THE THREE-DIMENSIONAL 'EXPLOSION' PROCESS

Abstract

We investigate an intensification mechanism for the magnetic field near the base of the solar convection zone that does not rely on differential rotation. Such mechanism in addition to differential rotation has been suggested by studies of flux emergence, which typically require field strength in excess of those provided by differential rotation alone. We study here a process in which potential energy of the superadiabatically stratified convection zone is converted into magnetic energy. This mechanism, known as the 'explosion of magnetic flux tubes', has been previously studied in thin flux tube approximation as well as two-dimensional magnetohydrodynamic (MHD) simulations; here we expand the investigation to three-dimensional MHD simulations. Our main result is that enough intensification can be achieved in a three-dimensional magnetic flux sheet as long as the spatial scale of the imposed perturbation normal to the magnetic field is sufficiently large. When this spatial scale is small, the flux sheet tends to rise toward the surface, resulting in a significant decrease of the magnetic field amplification.

Authors:
;  [1];  [2]
  1. Department of Earth and Planetary Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
  2. High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO 80307 (United States)
Publication Date:
OSTI Identifier:
22078454
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 759; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMPLIFICATION; APPROXIMATIONS; COMPUTERIZED SIMULATION; CONVECTION; DISTURBANCES; MAGNETIC FIELDS; MAGNETIC FLUX; MAGNETOHYDRODYNAMICS; POTENTIAL ENERGY; RADIOWAVE RADIATION; ROTATION; SOLAR ACTIVITY; THREE-DIMENSIONAL CALCULATIONS; TWO-DIMENSIONAL CALCULATIONS

Citation Formats

Hotta, H., Yokoyama, T., and Rempel, M., E-mail: hotta.h@eps.s.u-tokyo.ac.jp. MAGNETIC FIELD INTENSIFICATION BY THE THREE-DIMENSIONAL 'EXPLOSION' PROCESS. United States: N. p., 2012. Web. doi:10.1088/2041-8205/759/1/L24.
Hotta, H., Yokoyama, T., & Rempel, M., E-mail: hotta.h@eps.s.u-tokyo.ac.jp. MAGNETIC FIELD INTENSIFICATION BY THE THREE-DIMENSIONAL 'EXPLOSION' PROCESS. United States. doi:10.1088/2041-8205/759/1/L24.
Hotta, H., Yokoyama, T., and Rempel, M., E-mail: hotta.h@eps.s.u-tokyo.ac.jp. Thu . "MAGNETIC FIELD INTENSIFICATION BY THE THREE-DIMENSIONAL 'EXPLOSION' PROCESS". United States. doi:10.1088/2041-8205/759/1/L24.
@article{osti_22078454,
title = {MAGNETIC FIELD INTENSIFICATION BY THE THREE-DIMENSIONAL 'EXPLOSION' PROCESS},
author = {Hotta, H. and Yokoyama, T. and Rempel, M., E-mail: hotta.h@eps.s.u-tokyo.ac.jp},
abstractNote = {We investigate an intensification mechanism for the magnetic field near the base of the solar convection zone that does not rely on differential rotation. Such mechanism in addition to differential rotation has been suggested by studies of flux emergence, which typically require field strength in excess of those provided by differential rotation alone. We study here a process in which potential energy of the superadiabatically stratified convection zone is converted into magnetic energy. This mechanism, known as the 'explosion of magnetic flux tubes', has been previously studied in thin flux tube approximation as well as two-dimensional magnetohydrodynamic (MHD) simulations; here we expand the investigation to three-dimensional MHD simulations. Our main result is that enough intensification can be achieved in a three-dimensional magnetic flux sheet as long as the spatial scale of the imposed perturbation normal to the magnetic field is sufficiently large. When this spatial scale is small, the flux sheet tends to rise toward the surface, resulting in a significant decrease of the magnetic field amplification.},
doi = {10.1088/2041-8205/759/1/L24},
journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 1,
volume = 759,
place = {United States},
year = {2012},
month = {11}
}