Origin of Sunspots

  title={Origin of Sunspots},
  author={Donald Howard Menzel},
ALTHOUGH astronomers have commonly believed that sunspots are deep-seated vortices, the chief characteristics of a spot (an intense magnetic field and a cool umbra) have never been successfully explained. 
Gravitational-Magnetic Origin of Sunspots and Related Phenomena
A wholly satisfactory theory for the origin of sunspots has evidently not as yet been proposed. Contemporary approaches are generally founded upon the conviction that they originate somehow from
Origin of Sunspots
Sunspots, seen as cool regions on the surface of the Sun, are a thermal phenomenon. Sunspots are always associated with bipolar magnetic loops that break through the solar surface. Thus to explain
Non-axisymmetric component of the photospheric magnetic field
The longitudinal asymmetry of the photospheric magnetic field distribution is studied on the basis of the data of the Kitt Peak National Solar Observatory (synoptic maps for the period 1976 - 2016).
Asymmetry of Sunspot Distribution in Solar Cycles 12–24 and the Gnevyshev–Ohl Rule
The nonaxisymmetric component of the sunspot distribution (longitudinal asymmetry) is considered based on the Greenwich–USAF/NOAA data for 1874–2016. Vector summation was used to estimate the value
Solar Cycle Prediction
A review of solar cycle prediction methods and their performance is given, including forecasts for cycle 24, which will probably mark the end of the Modern Maximum, with the Sun switching to a state of less strong activity.