The Babcock Model describes a mechanism which can explain magnetic and sunspot patterns observed on the Sun. 400 year sunspot history A sunspot is a region on the Suns surface (photosphere) that is marked by a lower temperature than its surroundings, and intense magnetic activity. ... The Sun is the star at the centre of our Solar system. ...

A modern understanding of sunspots starts with George Ellery Hale, in which magnetic fields and sunspots are linked. Hale suggested that the sunspot cycle period is 22 years, covering two polar reversals of the solar magnetic dipole field. George Ellery Hale (June 29, 1868 – February 21, 1938) was an American solar astronomer. ... Current flowing through a wire produces a magnetic field (M) around the wire. ...

Butterfly diagram showing paired sunspot pattern. Graph is sunspot Wolfer number.

Horace W. Babcock proposed in 1961 a qualitative model for the dynamics of the solar outer layers: The Wolfer number (also known as the International sunspot number, relative sunspot number, Wolf number, or Zürich number) is a quantity which measures both the number and size of sunspots. ... 1961 was a common year starting on Sunday (link will take you to calendar). ...

• The start of the 22-year cycle begins with a well-established dipole field component aligned along the solar rotational axis. The field lines tend to be held by the highly conductive solar plasma of the solar surface.
• The solar surface plasma rotation rate is different at different latitudes, and the rotation rate is 20 percent faster at the equator than at the poles (one rotation every 27 days). Consequently, the magnetic field lines are wrapped by 20 percent every 27 days.
• After many rotations, the field lines become highly twisted and bundled, increasing their intensity, and the resulting buoyancy lifts the bundle to the solar surface, forming a bipolar field that appears as two spots, being kinks in the field lines.
• The sunspots result from the strong local magnetic fields in the solar surface that exclude the light-emitting solar plasma and appear as darkened spots on the solar surface.
• The leading spot of the bipolar field has the same polarity as the solar hemisphere, and the trailing spot is of opposite polarity. The leading spot of the bipolar field tends to migrate towards the equator, while the trailing spot of opposite polarity migrates towards the solar pole of the respective hemisphere with a resultant reduction of the solar dipole moment. This process of sunspot formation and migration continues until the solar dipole field reverses (after about 11 years).
• The solar dipole field, through similar processes, reverses again at the end of the 22-year cycle.

• The magnetic field of the spot at the equator sometimes weakens, allowing an influx of coronal plasma that increases the internal pressure and forms a magnetic bubble which may burst and produce an ejection of coronal mass, leaving a coronal hole with open field lines. Such a coronal mass ejections are a source of the high-speed solar wind.
• The fluctuations in the bundled fields convert magnetic field energy into plasma heating, producing emission of electromagnetic radiation as intense ultraviolet (UV) and X-rays.

For other meanings, see corona (disambiguation) The corona is the luminous atmosphere of the Sun extending millions of kilometres into space, most easily seen during a total solar eclipse, but also observable in a coronagraph. ... A coronal mass ejection (CME) is a solar event which involves a burst of plasma consisting primarily of electrons and protons (in addition to small quantities of heavier elements such as helium, oxygen, and iron). ... A solar wind is a stream of charged particles (i. ... Electromagnetic radiation is a propagating wave in space with electric and magnetic components. ... Ultraviolet (UV) radiation is electromagnetic radiation of a wavelength shorter than that of the visible region, but longer than that of soft X-rays. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz...

References

• Babcock, H. W. (1961). "The Topology of the Sun's Magnetic Field and the 22-Year Cycle". Astrophys. J. 133 (2): 527-587.