Magnetic storm, according to their data, began about 21:00 MSK and lasted six hours — to 03.00 MSK. Kp index of geomagnetic activity reached a value of 6, which corresponds to two points on the five-point grading scale adopted by the magnetic storms.
"While the storm occurred and not a record (above it is even more powerful three classes of events), the amplitude of such events were observed six months — from August 4, 2010. Last the storm that go beyond the strength was registered 10 months ago, on April 5 2010, when the index of geomagnetic storms reaching a maximum level of Kp = 7, "- said in a message on the site laboratory.
"The cause of the storm was the coronal mass ejection — the release of the hot plasma of the solar corona in the direction of the Earth, which occurred about three days ago," — said the laboratory RIA Novosti Sergei Bogachev.
This is the second magnetic storm of 2011. The first, relating to the minimum level, 1 in 5, occurred on the night of January 7, 2011 at the height of the holiday season. In 2010, over 365 days there have been 16 magnetic storms, and the year before that, in 2009, which coincided with the minimum of solar activity — only 4.
Index Kp, characterizing geomagnetic activity, was introduced in 1938 by the German geophysicist Julius Bartels (Julius Bartels). Kp The scale has 10 levels, from 0 to 3 are the quiet magnetosphere, level 4 — perturbed, and the levels of 5 to 9 — magnetic storms five classes. Planetary Kp index is calculated every three hours, by averaging data from 13 geomagnetic observatories between 44 and 60 degrees north and south geomagnetic latitudes.
In 2000, there were 12 in the world of higher magnetic storms, the fifth level, which led to the failure of power grids, radio blackouts and auroras, observed up to the equator. The last storm of the fifth level was on September 11, 2005.