The magnetic history of solar active regions

Citation

Mosher, James Marshall (1977) The magnetic history of solar active regions. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/ZPPR-4490. https://resolver.caltech.edu/CaltechETD:etd-08292008-105155

Abstract

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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.

Thesis Files