The Solar Maximum of the Year 2013 was reported to be the weakest in past 100 years. In the meanwhile, it was explained in the NASA’s Marshall Space Flight Center’s report released on 11 July 2013 onSolar Weather Cycle that in the year 2014, the solar maximum could be even more quiescent.
During a Solar Maximum, the number of sunspots increases. These dark temporary regions on the surface of the sun are thought to be caused by interplay between the sun's plasma and its magnetic field. In about every 11 years, the sun goes through a cycle defined by an increasing and then decreasing number of sunspots. Solar Cycle 24 has been underway since 2011 and its peak was expected in 2013, but fewer sunspots were observed this year as compared with the maximums of the last several cycles.
The sunspots occurring during a calm maximum have the same brightness and area as the ones observed during a more turbulent peak. The quiet maximum is allowing scientists to test their knowledge of how the sun works and hone their predictions of the strength of future solar cycles.
North-South, or meridional, flows carry magnetic elements from sunspots to the sun's poles, building up the polar magnetic fields until they eventually flip around the time of the solar maximum. Scientists noticed that the strength of the polar fields when a new cycle begins influences the strength of the cycle. For example, weak polar fields observed in 2008 led to the current weak cycle, while strong polar fields in 1986 spawned a strong Cycle 22.
The polar fields have been slowly reversing at this maximum, suggesting that they are not going to get much stronger during Cycle 24. This also sets the stage for an even smaller maximum during Cycle 25. A small Cycle 24 also fits in with a 100-year pattern of building and waning solar cycles. Scientists are not aware about the causes of this trend yet, but it was explained that there were weak solar cycles in the beginning of the 19th and 20th centuries.
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