Magnetic fields and supergranule velocity fields on the quiet sun

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5151271

Wang, H

The author has carried out detailed study on the quiet sun magnetic fields and supergranule velocity fields. This thesis consists of 6 themes. (1) He studied the statistical properties of quiet sun magnetic fields, including size distribution, evolution, flux budget of magnetic flux elements, and the magnetic diffusion constant. From the observations, he derived that the magnetic diffusion constant is {le} 150 km{sup 2}/sec in the quiet region. (2) He studied the supergranule velocity fields. By observing the evolution of individual supergranule cells, he found that the average lifetime of supergranules is {ge} 50 hours. (3) He measured the contrast of faculae near the solar limb. The measurements show no obvious contrast increase or decrease near the solar limb. The observation fits neither the hot wall nor hot cloud fluxtube model. (4) He measured the separation velocities of new bipoles. The observed values are several times smaller than the values estimated by the theory of magnetic buoyancy. (5) He applied the local correlation tracking technique to BBSO Videomagnetogram data and detected an approximate radial intranetwork flow pattern. (6) He studied the relationship between magnetic fields and convection velocity fields. He found that ephemeral regions have a light tendency to emerge at or near the boundaries of supergranules; supergranules have the same scale, correlation lifetime and mean horizontal speed in enhanced network region as in the mixed polarity quiet sun; the velocity of moving magnetic features that surround sunspots is consistent with the direct Doppler measurements.

• Research Organization: California Inst. of Tech., Pasadena, CA (USA)
• OSTI ID: 5151271
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CONVECTION
CORRELATIONS
DIFFUSION
ENERGY TRANSFER
HEAT TRANSFER
LIFETIME
MAGNETIC FIELDS
MAGNETIC FLUX
MAIN SEQUENCE STARS
MASS TRANSFER
MATHEMATICS
SOLAR ACTIVITY
SOLAR GRANULATION
STARS
STARSPOTS
STATISTICS
STELLAR ACTIVITY
SUN
SUNSPOTS
VELOCITY