FRACTAL PROPERTIES OF SOLAR ERUPTIONS AND INTERPLANETARY MAGNETIC FIELDS IN GEOMAGNETIC EVENTS

摘要

The 19.5 nm signal fluctuation across the solar disc and the interplanetary magnetic field (IMF) fluctuation across time were investigated for their fractal properties. The studied events were strong geomagnetic storms as measured by large negative Dst values. One atmospheric gamma ray burst event was also included. The selection criteria were based on our previous studies that the coronal mass ejection speed, solar energetic particle flux, and Dst index are strongly related to the IMF fluctuation and its fractal property (American Meteorology Society Space Weather Symposium 2006, paper 3.10). The results showed that the random series fractal dimension ranges about 1 to 2 in various conditions and appears to be correlated to that of the IMF time series. The result also showed that fractal dimension variation versus time could be used for characterization of solar eruption evolution. The percent increment data showed that the distribution average could change with time and could reverse polarity just before the explosion in several major solar eruption events.