Some results of the investigation received by using of DMSP spacecraft observations

In the papers by Vorobjev et al. [2000] and Starkov et al. [2002] the position and dynamics of different auroral precipitation regions depending on magnetic activity level was examined by using the statistical set of date and comparison of their position to boundaries of the auroral oval and diffuse aurorae was curried out.

The new notation of auroral precipitation regions was introduced in the investigation [Starkov et al., 2002] which is based on characteristics of precipitating particles and allows to describe uniformly the phenomena in all sectors of local geomagnetic time. This notation has allowed us to construct a global distribution of auroral precipitation at different values of AL and Dst indexes and to estimate a modification of a polar cap area depending on magnetic activity level [Starkov et al., 2003; Vorobjev and Yagodkina, 2005]. The analytical equations were derived which connect both the position and characteristics of auroral precipitation with magnetic activity [Vorobjev and Yagodkina, 2005, 2007]. The structure and dynamics of auroral precipitation during the periods of strong magnetic storms were investigated by Vorobjev and Yagodkina [2007].

The night-time location of the polar cap and auroral oval boundaries were investigated depending on orientation of the interplanetary magnetic field in the ecliptic plane [Vorobjev et. al., 2002]. It was shown that a value of the interplanetary Bx component significantly influences on the latitudinal position of high-latitude boundaries of auroral precipitation.

The empirical model of a substorm in midnight auroral precipitation was constructed by Vorobjev et al., [2003]. Typical variations of the IMF and solar wind plasma were determined in this research for an average substorm. The latitudinal position and dynamics of different precipitation regions as well as variations of the average energy and energy flux of precipitating electrons during substorm phases were shown in this investigation. Planetary distribution of auroral precipitation characteristics during substorm was reported in [Vorobjev et al., 2007]. The power of auroral precipitation during all substorm phases was investigated in paper by Vorobjev and Yagodkina [2008].

The affect of the solar wind plasma density on characteristics of auroral precipitation was examined by Vorobjev et al., [2004] and Vorobjev and Yagodkina [2006]. Authors showed that under quiet magnetic conditions (|AL|<100 nT, Bz>0) the increases in the solar wind plasma density from 2 up to 24 cm-3 were accompanied with a considerable (in 2 and more times) increase in the precipitating energy flux with simultaneous reduction of both precipitating ions and electrons average energy. The results Consequence of such changes will be decreases in auroral brightness in the UVI spectral region (LBH bands) and the change in colour of auroral luminosity from green to red (I6300>I5577, where I is the luminosity brightness).