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The magnetic history of solar active regions


Mosher, James Marshall (1977) The magnetic history of solar active regions. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/ZPPR-4490.


NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.

An attempt has been made to use recent magnetic observations to trace the history of a typical solar active region from birth to death. By comparing the short-term motions to the long-term spreading, it is demonstrated that the decay process is dominated, over periods ranging from days to months, by a random walk of field lines, with a diffusion constant of roughly 200-400 km[...]/sec. While the interaction between diffusion and differential rotation dictates the geometric pattern of the decaying region; the actual quantity of surviving flux appears to be less, and its ultimate annihilation more thorough, than would have been expected. This probably indicates a continued subsurface coupling between opposite polarity features. In addition, the long-range agreement between theory and observation is considerably improved by postulating the existence, in the middle latitudes of each hemisphere, of a systematic, poleward-moving meridional flow of about 3 m/sec.

The outlook for being able to make continued progress towards the understanding of basic solar phenomena by further efforts in this direction is promising.

Item Type:Thesis (Dissertation (Ph.D.))
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 November 1976
Record Number:CaltechETD:etd-08292008-105155
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3273
Deposited By: Imported from ETD-db
Deposited On:10 Sep 2008
Last Modified:21 Dec 2019 03:53

Thesis Files

PDF (Mosher_jm_1977.pdf) - Final Version
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