Physics of auroral phenomena : proceedings of the 36th Annual seminar, Apatity, 26 February – 01 March, 2013 / [ed. board: A. G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2013. - 215 с. : ил., табл.

4. For obtained in the previous step one-dimensional picture of the intensity distribution histogram is calculated in black on a scale from 0 (completely white) to 1 (completely black). 5. For all analyzed flares, and for each of the analyzed scale fluctuations are calculated histogram of the intensity distribution groups moments of complete synchronization of oscillations. The histograms corresponding to one scale are summarized and linked to the timeline. For ease of interpretation, the results expanded time axis so that the origin of the abscissa corresponds to the flare time. Histogram for oscillations with a period of 180 minutes presented on Fig. 1. Here clearly shows that there are extremes o f 2 and 3.5 days before the expansion of the flare. This corresponds to the sync moments of the horizontal component of the geomagnetic field in the studied events. In order to test the alternative hypothesis by impact of Solar wind parameters (flow velocity, density, and the magnitude of IMF) on the Earth's magnetosphere in the pre-flare intervals are calculated cumulative histogram of the intensity distribution groups moments of complete synchronization of oscillations in these parameters. An example of an appropriate analysis for the period of oscillation 180 min in Fig. 2 is shown. scale -180 min Identification o f long-period MHD fluctuations in the magnetosphere Fig. 2 The total amount of the normalized histogram moments synchronization of oscillations for near-Earth parameters for all the analyzed flares by period 180 min. On the horizontal axis represents time in days before the flare of class X. The moment of registration of flare is located at left. 4. Interpretation and verification of the results The resulting cumulative histogram of the normalized moments of horizontal sync component of the geomagnetic field in a wide geographic range in different ranges of periods for its extremes the connection with the phenomena of X-ray flares was demonstrate. With the increasing analyzed periods availability of extrema becomes more prominent. Extremes of histograms for oscillations with a period of 180 minutes, the most informative - they are marked with 2 and 3.5 days to extreme flare. scale - 180min Fig. 3 The total amount of the normalized histogram moments synchronization of oscillations at all stations for period of 180 minutes, when within 5 days there has been an flares of class M or X not observed. The y-axis represents the number of occurrences of the histogram moments of complete synchronization of oscillations at all stations. On the horizontal axis represents time in days. 57