What does a solar flare mean?

Solar flare? It is a kind of intense solar activity, which can release a lot of energy in an instant, causing local areas to heat up instantly and emit various electromagnetic radiation.

In the particle event emitted by flare, when the proton energy detected in geosynchronous orbit is greater than 10 MeV and the flux is greater than 10 PFU, it indicates that there is a strong proton flow in this event, that is, a proton event has occurred, and the corresponding source flare is called proton flares. White light flare is an extremely rare solar flare, so it is named because it can be observed in the white light range.

Guided by the interplanetary magnetic field in the Sun-Earth space, protons emitted from the eastern hemisphere on the surface of the sun generally cannot reach the Earth, so proton flares mainly occurs in the western hemisphere on the surface of the sun. Most flares in the proton flares are of magnitude M or above, and the proton events caused by them can be observed near the earth orbit within 1 ~2 hours after the occurrence.

Intensity of solar flare

The size of flare area is an important index of flare radiation scale. The area when flare brightness reaches the maximum is used as the main basis of flare level internationally, and the maximum brightness of flare is described qualitatively. According to the Hα monochromatic light area of flare, optical flare can be divided into five grades, which are denoted by S, 1, 2, 3 and 4 respectively.

Adding F, N and B after the horizontal indicates whether the maximum brightness of optical flare in Hα line is weak, normal or strong respectively. So the biggest and brightest flare is 4B, and the smallest and darkest flare is SF.

The ionosphere of the earth is sensitive to the change of solar soft X-ray radiation intensity, so the soft X-ray radiation intensity of 1~8 angstrom is widely used to classify X-ray flares internationally. According to the peak flux of soft X-rays observed by GOES satellite, flares are divided into five levels: A, B, C, M and X, and the released energy increases in turn.

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