Martínez Pillet, V.
Bibliographical reference
Astronomische Nachrichten, vol. 323, no. 3/4, p. 342-348
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7
2002
Citations
59
Refereed citations
52
Description
The photometric decay of sunspots is studied in some detail. Aspects
related to leader vs. follower sunspot decay are presented and our
current understanding of the physical mechanisms involved critically
reviewed. The intrinsic instability of follower spots to form a stable
sunspot cannot be understood in terms of the fluting stability as
proposed long time ago. For leader sunspots, the slow decay phase is
considered in the light of diffusive models that spread the flux of the
spot over a larger area. It is shown that the Moving Magnetic Feature
(MMF) phenomenon, while probably part of the decay process, has an
origin not related to the decay process itself. Magnetic flux losses
from leader sunspots are 3 to 8 times slower than the pace of net flux
generation seen in the moat region. It is argued that MMFs are
originated from the interaction of the field free convection (moat
flows) and the Evershed magnetized channels outside the spot.