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The Sun flips its magnetic field every 11 years

18 August 2021
Electromagnetism

This intriguing statement is at https://phys.org/news/2021-08-fast-solar-seasons-sun-clock.html … the Sun flips its magnetic field every 11 years. How does it do that? A new mystery for science it would seem.

No two solar cycles are the same in amplitude and duration. To study the solar seasons scientists intend to build a sun clock – or may already have done so. This will be done using daily sunspot number records – which have been kept since 1818. The sun clock maps the changing solar cycles providing a roughly 22 year magnetic cycle. This is split into two eleven halves – one up and one down. Once the sun clock is built scientists will be able to see the switch from solar maximum to the descenting phase, which happens fast. There is also a difference in the duration of the declining phases when the sun's magnetic polarity was 'up' compared to 'down'. The incoming cycle, solar cycle 25 has already arrived, is going to be short, they claim. Sandra Chapman of the University of Warwick Dept of Physics is cited as a spokesperson. She says, 'I think it is remarkable that something the size of the sun can flip its magnetic field every eleven years, and going up is different to going down. Somehow, the sun knows which way up it is and this is an intriguing problem, at the heart of how the sun generates its magnetic field.'

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