Good evening, my dear friends!
Today I begin today the series of educational posts about space weather.
A. Active Region ( AR).
The active region on the Sun (not to be confused with the spot) is a set of active formations (spots, prominences, etc.) and non-stationary dynamic phenomena (flares, magnetic fluxes) in the solar atmosphere.
The active area is characterized by various indices of solar activity: the number of Wolff (the relative Zurich number of sunspots), the total area of sunspots, the total flux of radio or X-ray radiation,
Today, on June 26, 2017, there is only one active region on the Sun - number 12664.
Visual demonstration of the behavior of two active regions in different wavelengths according to SDO - Solar Dynamic Observatory.
The above video shows images from August 15 to August 17, 2011. We can compare the activity of this area at three different wavelengths. The left plasma near the surface of the Sun (red) is shown at a temperature of up to 60 000 K (304 Angstroms, ultraviolet). The middle part (yellow) shows a plasma with a temperature of about a million K (171 Angstroms, ultra-ultraviolet). The right part (gray) shows the magnetic field of sunspots, which, in the final analysis, is the source of solar activity.
Thank you for your attention, your 