No material we know of on Earth can withstand the temperature of nearly 6,000k found on the surface of the Sun and still stay in one stable structure as how the sunspots show. The heaviest element Osmium has a mass density of 22.6 g/cm^3 with a boiling point of 5285k, above which no one stable piece of osmium can be found. The next material found with higher mass density is neutron stars. All these potentially lead us to believe that sunspots are composed of material of mass density far higher than osmium. But what is its material nature?
With volumes that can reach even 1,000 times of that of the Earth, together with the unusually high mass density, the sunspots must have response to the gravitational influence from all the planets conspicuously different from the fluidic materials in their environment. The gravitational influence from the planets on the Sun is just an inescapable reciprocal response to the gravitational force from the Sun onto the planets. Therefore, as part of the Sun, the sunspots must be responsible of the exertion of the influence as well as sharing the corresponding reciprocal response from the planets.
When the size of the sunspot is mentioned in our study, we have been getting used to a concept that is portrayed by terms like contract, expand, and decay. If gravitational influence from the planets cannot be excluded in a reasonable speculation, we may have to include one more concept that is portrayed by the term ``buoyancy". As such, the visual effect of contracting in our view happens when a sunspot sinks deeper and deeper below the Sun's surface, whereas the visual effect of expanding happens when the sunspot resurfaces and exposes itself more and more in our view. So, given the unusually high mass density of the sunspots, true decaying of them in the sense of material integrity may not be a reality that our study can pursue.
Looking at whether the sunspots should have response to the gravitational influence from the planets, we cannot escape from the awareness of two numbers that are very close in value. One of them is the more or less than 11 year beat of the rhythm shown by the maximum and minimum of the sunspot population; the other is the 11.86 year period of Jupiter's orbital movement. In case the gravity of Jupiter does have influence on the cycle of sunspots, what about other planets? Further, we must be aware of that the Sun's spinning axis tilts by an angle of 7.5 degrees with respect to the ecliptic, but when a solar maximum begins, the initial few spots always show up near the 45 degrees latitude, north or south. Will the Sun's axial tilt also play a role in affecting the sunspot cycle?
Documents show that the Sun's magnetic field strength distributes itself differently across the surface of the Sun. At its polar field, the strength is found to be 1-2 gauss, whereas it is typically 3,000 gauss in areas where sunspots populate, and 10-100 gauss in solar prominences. Such field strength distribution thus reveals to us the following typical features: (1) the field strength at areas near the equator is far stronger than that near the polar area; (2) while the field is strong near the equator, it is further concentrated at where the sunspots show up; (3) number of the sunspots in our vision displays no direct proportional relationship with the overall strength at where they show up; (4) that 10-100 gauss is found in solar prominences conversely means that the field strength of each sunspot is comparatively weak until some chance is introduced together with a prominence.
Features (1) and (2) can be hypothetically realized by such an arrangement: A strong magnetic bar is placed deep below the surface of the Sun and this bar always has its pole pointing at about the equator, but never at either of the Sun's poles. Feature (3) removes the possibility that the strong magnetic strength near the equator is solely contributed by the sunspots; therefore this reasoning further emboldens a believing that a separate magnetic source other than the sunspots owns this strong field. Being not the source, however, the sunspots' appearance can serve as an index to help tracing how this source has been moving. Is it only coincidence that sunspot never appears at the pole where the magnetic strength is so weak? Feature (4) further witnesses that each sunspot is a weak magnet compared to the one hypothetically assumed existing far below the Sun's surface.
Reasoning in this article based on observation leads to a believing that the Sun is consisted of three basic material layers: (1) the out-most layer, which, in a state of plasma, is the layer in our daily view, and shall be called the fluidic crust of the Sun in this article; (2) deep below this crust is a zone that hosts the absolute major thermonuclear reactions of the Sun; (3) further below the nuclear reaction zone is the core body of the Sun, a spheroidal volume of exceedingly high mass density. This spheroidal dense volume shall be called the yolk of the Sun in this article. This yolk is embraced by numerous nuclear reactions, which happen all over on the yolk's surface in an isotropic manner with respect to the center of the Sun. Floating on this dense massive yolk is a gigantic magnetic material body MMB), which should have contained no less mass than all the sunspots put together, and its material nature should be essentially the same as that of the sunspots.
Floating on the yolk with mass far exceeding what our Earth has, this MMB cannot escape from the governing action exerted on it by the gravitational force from the planets, particularly Jupiter. Being a gigantic magnetic carrier, its whereabouts must in turn orchestrate the debuting and hibernation of the population of those magnetic sunspots through magnetic reaction. In comparison to this giant MMB, each sunspot is merely a magnet droplet, even if such droplet may reach a volume as big as 1000 times of the Earth. From this thread of reasoning, let's further pursue how the MMB and each sunspot are to form various magnetic "tube" that guides the appearance of prominence, solar flare, and subsequently the coronal mass ejection.