On Earth, the magnetic storm began associated with X-class flare on 15 February
19.02.11. On Earth began geomagnetic disturbances caused by flash X-class, which occurred February 15, 2011. Upcoming disturbance rather confidently predicted three days ago, as the observations of space coronagraphs were visible large masses of ionized gas ejected from the Sun is in the direction of Earth. According to preliminary estimates of the speed of about 400 km / s, the bulk of the plasma should have reached Earth's orbit in the afternoon of 18 February, and the first front — ahead of a period of several hours to days.
According to the American satellite measurements ACE, located on the line between Earth and the Sun at a distance of about 1 million miles from Earth, the first contact with the discarded plasma clouds were about 4 am, Moscow time, on the growth rate of the ambient solar wind, from 300 to 600 km / s, as well as increase the density and temperature of the surrounding plasma. As of 13 am Moscow time land was to plunge into the cloud ejected from the Sun to 10-15 million km. Currently, there is a gradual decrease in speed and increase in the concentration of the surrounding matter, talking about the approach to the planet core slower and dense masses of material. For the past eight o'clock there were also quite a few sudden changes in the density of the surrounding plasma, indicating that the release has a rather complex internal structure, which is more sparse areas interspersed with dense domain.
As of 13 am Moscow time the level of disturbance of the magnetic field increases from Kp = 1, at the beginning of the day, up to Kp = 5, which corresponds to the minimum level at which the oscillations of the magnetosphere begin to be classified as a magnetic storm. According to preliminary estimates, during the day it could rise to the level of Kp = 6, and in some bursts — up to Kp = 7. The main difference that characterizes the disturbance of strong flares is, nevertheless, not only by their strength as duration. Even if the magnetic storm will not reach a high score, finally stabilize the Earth's magnetosphere, may not be able to start tomorrow.