Right now, the Sun is extremely active, erupting strong solar flares that cause radio blackouts on Earth. All of this is part of an 11-year cycle in which the poles of the Sun reverse.
The Schwabe cycle is an 11-year cycle in which there is an increase and drop in sun activity. Heinrich Schwabe, a German amateur astronomer, watched the Sun between 1826 and 1843 and found that it spins on its axis once every 27 days. He observed that the Sun changes over eleven years from tranquil phases, during which no sunspots are visible, to maximum phases, during which at least twenty sunspot groups are seen.
Because the Sun’s equator rotates more quickly than its poles, it stirs up changes in the magnetic field of the Sun that result in these sunspots.
“The Sun’s magnetic fields rise through the convection zone and erupt through the photosphere into chromosphere and corona,” according to NASA. “The eruptions lead to solar activity, which includes such phenomena as sunspots, flares, prominences, and coronal mass ejections.”
During the cycle, the Sun’s magnetic field flips, resembling a far more fluid Earth. The cycle may last eight years or fourteen years. One pole is positively charged while the other is negatively charged during the solar minimum, which is the lowest point of sunspot activity.
Throughout the solar cycle, the magnetic structure of the sun varies. According to one study on the subject, “it has a dipole structure during solar minimum, where the open flux extends mainly from the polar regions into the interplanetary space.”
It doesn’t stay in that dipole form for very long because the Sun’s revolution causes its magnetic field to twist, accelerating the cycle.
“During maximum, a complex structure is formed with low-latitude active regions,” the article adds, “and weakened polar fields, resulting in spread open field regions.”
So where is the cycle at this point? The Sun is already becoming more active, and it is expected that this year’s next solar maximum will occur between January and October.
However, one group thinks they have a better estimate by examining something known as “terminator events.” The group examined magnetic donuts, which develop on both hemispheres of the Sun at a latitude of 55 degrees. The researchers named this formation, which migrates in the direction of the equator and meets and cancels each other out, a Hale cycle (two solar cycles) terminator.
The scientists thought they could improve their forecasts about the solar cycles by concentrating on these terminator episodes, which often occur up to two years after the minimum.
“If you measure how long a cycle is, not the minimum to minimum, but from terminator to terminator, you see that there is a strong linear relationship between how long one cycle is and how strong the next one is going to be,” Robert Leamon, a researcher at NASA, told Space.com
They forecast that the magnetic field will reverse using these techniques in the middle of 2024, a few months ahead of the solar maximum.
