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    		• Solar Cycle and Solar Activity

    Solar Cycle and Solar Activity

         Monthly averages of the sunspot numbers show that the number of sunspots visible on the Sun waxes during solar maximum, and wanes during solar minimum, with an approximately eleven year cycle. Plot is courtesy of David Hathaway, NASA MSFC.



         The solar cycle is a period of 22 years in which the sun's magnetic field rotates a full 360 degrees, causing its poles to switch. Solar maximum is the maximum solar activty that takes place approximately every eleven years, while solar minimum is the lowest point of solar activity. The number of Coronal Mass Ejections(CME's) increase and decrease. Coronal Mass Ejections can interact with the normal solar wind and interact with the Earth's magnetic field causing geomagnetic storms(see Solar Wind Consequences and Space Weather). As the number of sunspots increase the number of Coronal Mass Ejections increase. CME's are more strongly associated with geomagnetic storms on Earth than Flares.

         Flares may occur in conjunction with Coronal Mass Ejections, but may also occur without corresponding CME's. Smaller flares tend to follow the eleven year cycles at its climax of several tens of flares per day. The larger flares usually occur fewer times than smaller flares during solar maximum.

    This page was researched and compiled by Robert (RC)