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The evolution of a horizontal scale for oscillatory magnetoconvection

Journal Article:

Abstract

Oscillatory convective motions have been observed in the umbrae of sunspots and, in the past, the linear theory of overstability has been used for sunspot models. Here a non-linear model for oscillatory convection has been used to investigate the possibility of a preferred horizontal cell size for these motions, in the presence of a magnetic field. The integration forward in time, from the conductive state, of the non-linear multimode equations governing magnetoconvection when the magnetic Prandtl number is less than one portrays a complex interaction between the evolving magnetic and vertical velocity horizontal scales. Preferred horizontal scales for the convective cells have been established by identifying the modes that substantially contribute to the overall convective heat transport. All other modes, although initially perturbed, in time essentially decay to zero through self interaction. 8 refs., 5 figs.
Authors:
Murphy, J O; [1]  Lopez, J M [2] 
  1. Monash Univ., Clayton (Australia). Dept. of Mathematics
  2. Aeronautical Research Labs., Port Melbourne (Australia). Aerodynamics Div.
Publication Date:
Jan 01, 1989
Product Type:
Journal Article
Reference Number:
AIX-21-016759; EDB-90-037028
Resource Relation:
Journal Name: Proceedings of the Astronomical Society of Australia; (Australia); Journal Volume: 8:1
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; SUNSPOTS; CONVECTION; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; NONLINEAR PROBLEMS; OSCILLATIONS; WAVE FUNCTIONS; ENERGY TRANSFER; FLUID MECHANICS; FUNCTIONS; HEAT TRANSFER; HYDRODYNAMICS; MASS TRANSFER; MECHANICS; SOLAR ACTIVITY; STARSPOTS; STELLAR ACTIVITY; 640104* - Astrophysics & Cosmology- Solar Phenomena
OSTI ID:
5076209
Country of Origin:
Australia
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0066-9997; CODEN: AAUPB
Submitting Site:
INIS
Size:
Pages: 25-28
Announcement Date:
Mar 01, 1990

Journal Article:

Citation Formats

Murphy, J O, and Lopez, J M. The evolution of a horizontal scale for oscillatory magnetoconvection. Australia: N. p., 1989. Web.
Murphy, J O, & Lopez, J M. The evolution of a horizontal scale for oscillatory magnetoconvection. Australia.
Murphy, J O, and Lopez, J M. 1989. "The evolution of a horizontal scale for oscillatory magnetoconvection." Australia.
@misc{etde_5076209,
title = {The evolution of a horizontal scale for oscillatory magnetoconvection}
author = {Murphy, J O, and Lopez, J M}
abstractNote = {Oscillatory convective motions have been observed in the umbrae of sunspots and, in the past, the linear theory of overstability has been used for sunspot models. Here a non-linear model for oscillatory convection has been used to investigate the possibility of a preferred horizontal cell size for these motions, in the presence of a magnetic field. The integration forward in time, from the conductive state, of the non-linear multimode equations governing magnetoconvection when the magnetic Prandtl number is less than one portrays a complex interaction between the evolving magnetic and vertical velocity horizontal scales. Preferred horizontal scales for the convective cells have been established by identifying the modes that substantially contribute to the overall convective heat transport. All other modes, although initially perturbed, in time essentially decay to zero through self interaction. 8 refs., 5 figs.}
journal = {Proceedings of the Astronomical Society of Australia; (Australia)}
volume = {8:1}
journal type = {AC}
place = {Australia}
year = {1989}
month = {Jan}
}