The Corona
The corona is the final layer of the sun. It consists of plasma, and is wider than the other layers combined, extending millions of miles into space. It cannot normally be seen, but during an eclipse, or with a coronagraph (which blocks out the suns light), it appears as a whitish haze around the sun. The corona is the subject of one of the greatest mysteries of the sun;the temperature in the corona far exceeds that of the surface of the sun, reaching over 8 million kelvin. There are some theories for why this may be
- Wave heating
The sun may be heated through Alvfen waves, which can carry large quanitites of energies. However, this type of wave does not disperse energy quickly enough. Some computer models have shown that this may be avoided, as the waves may be able to transform at the base of the corona. Evidence has shown that there are some less energy-dense waves penetrating the corona, but none enough to carry the energy needed.
- Magnetic Reconnection
A phenomena in which magnetic fields split and connect to other fields. While magnetic fields are usually bound to physical matter, plasma is unstable enough that they can be "churned", or split and reconnected. While this definetly occurs on the surface of the sun, no evidence has been shown that there enough flare to vbring the needed heat energy into the corona
Solar flares
Solar flares are a very well-known solar phenomena, but thier cause is still debated on. The most popular theory is that they are caused by the aforementioned magnetic reconnection, which is theorized to produce eruptions of electromagnetic radiation, which is what Solar flares are. They occur in sync with the 11-year solar cycle, and are often accompanied by
Coronal Mass EjectionsCoronal mass ejections (CMEs) are expulsions of electromagnetic field and plasma matter into the solar system. The cause of CMEs is thought to be similar to that of solar flares, however, no direct evidence has been found linking magnetic feilds to CMEs. A very small portion of CMEs make it to earth and can cause distruptions in our atmosphere by interacting with the magnetic field, such as aurora and distruption of radio and satelites.
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