Solar Cycle

daily rise and setting of the sun

The solar cycle, or the solar magnetic activity cycle, is the dynamical engine and energy source behind all solar phenomena driving space weather. Powered by a hydromagnetic dynamo process relying on the inductive action of internal solar flows, the solar cyclestructures the sun's atmosphere, corona and wind;modulates the solar irradiance;modulates the flux of short-wavelength solar radiation, from ultraviolet to X-Ray;modulates the occurrence frequency of flares, coronal mass ejections, and other geoeffective solar eruptive phenomena;indirectly modulates the flux of high-energy galactic cosmic rays entering the solar system.
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The variation in the activity of the Sun during an eleven year period. The solar cycle is most noticeable because of its effect on the number of sunspots visible on the photosphere . At the start of the cycle, known as the solar minimum, there are no sunspots for several weeks. The sunspots then appear at mid latitudes, 30° to 40° either side of the equator. During the next five years, the sunspots continually appear and disappear, moving towards the equator and displaying an overall increase in number as they do so. After reaching a sunspot maximum, the sunspots continue to move towards the equator but decrease in number over the next six years. The sunspots finally arrive at approximately 7° latitude and gradually disappear. Sunspots then begin to appear at 30° to 40° again but with a reversal in their magnetic polarity. All solar activity is linked to the solar cycle.