Numerical study of compressible magnetoconvection with an open transitional boundary

Technical Report · Wed Aug 01 00:00:00 EDT 1990

DOI:https://doi.org/10.2172/6577239· OSTI ID:6577239

Hanami, H; Tajima, T

We study by computer simulation nonlinear evolution of magnetoconvection in a system with a dynamical open boundary between the convection region and corona of the sun. We study a model in which the fluid is subject to the vertical gravitation, magnetohydrodynamics (MHD), and high stratification, through an MHD code with the MacCormack-Donner cell hybrid scheme in order to well represent convective phenomena. Initially the vertical fluid flux penetrates from the convectively unstable zone at the bottom into the upper diffuse atmosphere. As the instability develops, the magnetic fields are twisted by the convection motion and the folding magnetic fields is observed. When the magnetic pressure is comparable to the thermal pressure in the upper layer of convective zone, strong flux expulsion from the convective cell interior toward the cell boundary appears. Under appropriate conditions our simulation exhibits no shock formation incurred by the fluid convected to the photosphere, in contrast to earlier works with box boundaries. The magnetic field patterns observed are those of concentrated magnetic flux tubes, accumulation of dynamo flux near the bottom boundary, pinched flux near the downdraft region, and the surface movement of magnetic flux toward the downdraft region. Many of these computationally observed features are reminiscent of solar observations of the fluid and magnetic structures of their motions.

• Research Organization: Texas Univ., Austin, TX (USA). Inst. for Fusion Studies
• Sponsoring Organization: DOE/ER; Japan Society for the Promotion of Science (JSPS); NMFOUN; National Science Foundation (NSF)
• DOE Contract Number: FG05-80ET53088
• OSTI ID: 6577239
• Report Number(s): DOE/ET/53088-450; IFSR-450; ON: DE91000148; TRN: 90-030198
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
SOLAR CORONA
CONVECTION
BOUNDARY CONDITIONS
COMPUTERIZED SIMULATION
MAGNETOHYDRODYNAMICS
SHOCK WAVES
SUN
ATMOSPHERES
ENERGY TRANSFER
FLUID MECHANICS
HEAT TRANSFER
HYDRODYNAMICS
MAIN SEQUENCE STARS
MASS TRANSFER
MECHANICS
SIMULATION
STARS
STELLAR ATMOSPHERES
STELLAR CORONAE
640104* - Astrophysics & Cosmology- Solar Phenomena