CfA: The Secret of Magnetic Cycles in Stars

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CfA: The Secret of Magnetic Cycles in Stars

Post by bystander » Tue Aug 01, 2017 4:20 pm

The Secret of Magnetic Cycles in Stars
Harvard Smithsonian Center for Astrophysics | 2017 Jul 26
[c][attachment=0]SolarMagneticField.jpg[/attachment][/c][hr][/hr]
Using new numerical simulations and observations, scientists may now be able to explain why the Sun's magnetic field reverses every eleven years. This significant discovery explains how the duration of the magnetic cycle of a star depends on its rotation, and may help us understand violent space weather phenomena around the Sun and similar stars.

During what is known as the solar cycle, the magnetic field of the Sun has reversed every 11 years over the past centuries. This flip, where the south magnetic pole switches to north and vice versa, occurs during the peak of each solar cycle and originates from a process called a “dynamo”. Magnetic fields are generated by a dynamo, which involves the rotation of the star as well as convection and the rising and falling of hot gas in the star's interior.

For the Sun, scientists know that magnetic fields originate in its turbulent outer layers and have a complex dependency upon how quickly the Sun is rotating. Scientists have also measured magnetic cycles for distant stars with fundamental properties similar to those of the Sun. By studying the characteristics of these magnetic properties, scientists have a very promising way to better understand the magnetic evolution in our Sun associated with the dynamo process. ...

Reconciling solar and stellar magnetic cycles with nonlinear dynamo simulations - A. Strugarek et al
Attachments
This combination of images and artist’s impression shows changes in the <br />Sun’s appearance and magnetic fields during part of the solar cycle. The <br />Sun’s magnetic field flips approximately every 11 years, defining this cycle. <br />The switch happens around at the maximum peak of magnetic activity, when <br />sunspot and flare activity reaches its peak. We show images of the Sun <br />captured by NASA's Solar Dynamics Observatory (SDO) combined with <br />artist's impressions to show the magnetic field of the Sun.<br /><br />Images: NASA/SDO/A. Strugarek et al; Illustrations: L. Almeida, <br />Federal University of Rio Grande do Norte (UFRN), Brazil
This combination of images and artist’s impression shows changes in the
Sun’s appearance and magnetic fields during part of the solar cycle. The
Sun’s magnetic field flips approximately every 11 years, defining this cycle.
The switch happens around at the maximum peak of magnetic activity, when
sunspot and flare activity reaches its peak. We show images of the Sun
captured by NASA's Solar Dynamics Observatory (SDO) combined with
artist's impressions to show the magnetic field of the Sun.

Images: NASA/SDO/A. Strugarek et al; Illustrations: L. Almeida,
Federal University of Rio Grande do Norte (UFRN), Brazil
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