ИСТИНА

The data of observations using a method of partial reflections of the lower ionosphere above Tumanny (69.0 N, 35.7 E) during powerful solar X-ray flashes in the period from December, 5 till December, 14, 2006 are presented. According to the results of satellite observations over the period 4 X-ray flashes of X class, 5 flashes of M class, and about 30 flashes of C class occurred on the Sun. From the most powerful flashes only two flashes of classes X9 (on December, 5) and M7 (on December, 6) took place, when the lower ionosphere above Tumanny was illuminated by the Sun. During the solar disturbances the strong change of lower ionosphere structure and extraordinary high increase in electron concentration up to the values of 3·103 cm-3 at heights of 50-60 km were fixed. During almost the entire period of observations the lower ionosphere above Tumanny was in disturbed condition. As the majority of flashes took place, when the region of observations was on the dark side of the Earth it is possible to explain the marked disturbances of the ionosphere by powerful emissions of solar substance and high-energy solar particles.