Interplanetary Field Strongly Influences Solar Magnetic Flux
Magnetic Flux is responsible for the formation of solar flares, sunspots and coronal mass ejections. Scientists have discovered that flux variability on the sun is 80% correlated to variability in the interplanetary magnetic field that encompasses our solar system.
For the longest time solar physicists would observe more active parts of the sun in order to figure out the amount of magnetic flux in an isolated area. It wasn’t until the 1970s that they started measuring the suns net magnetic field. This was actually how they measured the flux of distant stars at the time and it does make a lot of sense because the sun tends to act more like a large electromagnetic dynamo with emergent properties rather then something you can fully understand by breaking it down in to parts.
Most solar activity of any significance occurs within 30 degrees of the equator on either side, and a lot of the time the amount of sunspots/solar flares that occur on one side of the equator do not match the other. Most of this imbalance has to due with the suns northern magnetic field being stronger then its southern field but regardless scientists managed to figure out the average field strength over time. What they did was add the accumulative strength of every solar event together and then divide any results by the amount of phenomena used as a reference point. This gives you a “mean” value.
By doing so we’ve learned that the suns field strength can vary between 0.2 G to ± 2 G over the course of history. So with that being said now the goal is to figure out whether or not thos variability matches that of the interplanetary magnetic field encompassing our solar system.
Using information gathered from the Solar Dynamics Observatory researchers included several different phenomena as indicators of magnetic flux.
- sunspots, dark spots that appear in the Sun’s photosphere as magnetic flux emerges;
- plages (an unusually bright region on the sun) enhanced networks, and active networks, surface features created by emergence and dispersion of weaker magnetic fields; and
- the Sun’s large-scale magnetic field — i.e., background regions that don’t fall into categories (1) and (2).
Bose and Nagaraju found out that about 89% of the variability in mean solar magnetic flux resulted from influences of the interplanetary magnetic field, whereas only ~10% of the magnetic flux was because of bright regions on the sun (plages) and the network field of flux ropes inside.
They also make the distinction that this study covers only the suns variability in mean magnetic flux, not it’s amplitude. That is – do the exact highs and lows match that of the interplanetary magnetic fields energy? Perhaps this will be revealed in another study.
What is particularly interesting is that they have recently figured out how to stabilize hot plasma in a nuclear fusion reactor by replicating this kind of magnetic flux.