de la Rosa, I. G.
Bibliographical reference
Solar Physics (ISSN 0038-0938), vol. 112, no. 1, 1987, p. 49-58.
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3
1987
Citations
51
Refereed citations
48
Description
A study of the observations made on the development and, in some cases,
even the decay of 15 large active regions is presented. It is shown that
the mature spots results from the subphotospherically controlled
attraction of several large fragments of 1-2 x 10 to the 21st Mx, which
are themselves made of smaller elements. The fragments are more stable
structures than the spots they constitute; and usually survive after the
spot decay. In the process of coalescence of fragments to form the spot,
the fusion is never complete and properly exposed photographs reveal
light bridges or saddlelike distributions of umbral dots in the
interstices between fragments. These are also the regions along which
the breakup of the spot occurs. These observations fit within the
expectations of the penetrative convection mechanism for umbral dots
proposed by Parker (1979).