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A Videomagnetograph Study of Diffusion of Solar Magnetic Fields in Weak Plage Regions


Smithson, Robert Carroll (1972) A Videomagnetograph Study of Diffusion of Solar Magnetic Fields in Weak Plage Regions. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/QGBD-XQ45.


A new instrument for use in astronomical research has been developed. This is the differential video photometer, a device for detecting differences in light intensity between two television pictures. With a suitable source of video, the device is capable of detecting intensity differences of the order of one part in one thousand. It should be useful in many applications, such as colorimetry, polarimetry, motion detection, and doppler shift measurements. It has been used thus far primarily as a videomagnetograph which measures the line-of-sight component of the solar magnetic field in the photosphere. Sensitivity to magnetic field strength is on the order of 5 to 10 gauss.

A study has been made of the characteristics of magnetic flux diffusion in weak plage regions. Points of enhanced magnetic field have been found to exist which have lifetimes of about 3 to 4 days, and which move in a random walk with a step time short compared to 24 hours. The random walk of these points considered as discrete entities is not, however, responsible for much of the flux diffusion in the weak plage regions. The R.M.S. displacement of the points is about 7800 km in 24 hours. A second form of flux transport has been found in which in a period of a few hours, a previously stable point will become unstable, and either shoot out a tongue of flux, or begin to move as a unit. This process can move flux over distances of the order of 10,000 km at apparent velocities of 1 to 2 km/sec. This process may be responsible for most of the flux transport in weak plage regions.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Physics)
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Leighton, Robert B.
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1972
Record Number:CaltechETD:etd-08212008-142413
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3189
Deposited By: Imported from ETD-db
Deposited On:29 Aug 2008
Last Modified:02 Jul 2024 21:42

Thesis Files

PDF (Smithson_rc_1972.pdf) - Final Version
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