It’s not just the planets that have magnetic fields. The Sun also has a very large and dynamic magnetic field.
The sun’s magnetic field is formed much like on Earth and Jupiter. There are convection cells that bring heat from the sun’s heat sources to the surface. These convection cells, and the sun’s rotation period of 25.4 Earth days produce the sun’s magnetic fields. However, there are many notable differences.
The sun is over 12,000 times larger than the Earth, which means that its magnetic fields are larger as well. It’s so large, it extends past the orbit of Pluto. However, it isn’t a solid object, like Earth. The sun’s material is mostly plasma, which works like a gas; like Jupiter. This means that the sun experiences differential rotation, where the equator rotates faster than the poles. On the sun, its Equator rotates every 25.4 days, but its poles rotate every 29 days. This video will demonstrate what that does to the sun.
When the sun rotates, the equator stretchs the magnetic field lines towards the sun’s direction of rotation, and it will keep stretching it until they snap like rubber bands. When they snap, they release the energy in the magnetic field and the magnetic field lines pop out of the sun. These magnetic field lines cause the charged particles from the surface to become trapped along the magnetic field lines. Those trapped particles are called prominences. In addition, Sunspots are formed where the magnetic field lines poke out and in, when the charged particles are lifted from its surface. That is why sunspots are common during periods of high solar activity, like the Solar Maximum.
Eventually, the magnetic field lines will reconnect with each other, and release a lot of energy, leading to large solar flares, and coronal mass ejections. At the same time, the polarity of the magnetic fields will reverse. When the flip is complete, the sun’s magnetic field will drop to zero, reappear in its reversed polarity, and start the process again. This process occurs every 11 years and after each cycle, the poles reverse.
Today, there is evidence that the Sun’s magnetic field is in the process of flipping after a chaotic solar maximum. Once the flip is complete, the process starts again.
Here is a video that talks about the sun and its solar cycle by NASA:
Thank you for reading! For my next topic, I want to hear from you. What do you want me to write about next time? You can respond by going to the contact form at: http://www.jolyastronomy.com/contact-me/ Thank You.
Coursera Lecture 6.6