Rolf Werner    Time Series Analysis by descriptive statistic

Rolf Werner    Time Series Analysis by means of inference statistical methods

Georgeta Maris    Periodicities of the Solar Wind and its Fast Streams

Irina Despirak, Andris Lubchich, Veneta Guineva
Development of substorm bulges during storms of different interplanetary origins
Abstract: Different structures in solar wind are observed depending on the type of solar activity: magnetic clouds (MC), recurrent streams (RS), and regions of their interaction with undisturbed solar wind (Sheath and CIR). Three of these structures, namely, Sheath, CIR, and MC, are the sources of geomagnetic storms. Furthermore, the storms originating from these three sources differ in intensity, recovery phase duration, etc. We have searched for distinctions in the development of substorm bulges occurring during geomagnetic storms connected with the MC, Sheath and CIR. Solar wind parameters were taken from the Wind spacecraft observations and the auroral bulge parameters were obtained by data from the Ultra Violet Imager onboard Polar. The longitudinal and latitudinal dimensions of the auroral bulges, the poleward aurora propagation and the onset latitude of auroral bulge were determined. It was shown that auroral bulges "geometry" is different for these types of storms. The largest sizes of auroral bulge were found for CIR- and Sheath-storms situations. The latitudinal size of the auroral bulge during MC-storms is smaller, but the longitudinal size is larger. As consequence, the ratio between longitudinal and latitudinal sizes for substorms during MC is also larger. We suggest this latter feature is explained by different configuration of the near-Earth magnetotail during CIR- and MC-storms

Oksana Yagodkina, Irina Despirak, Veneta Guineva
Spatial distribution of the auroral precipitation zones during storms connected with magnetic clouds
Abstract: The dynamics of the electron precipitation boundaries was examined using the DMSP satellite data and empirical model in which the boundary location depends on the geomagnetic disturbance level expressed by the AL- and Dst indices. The solar wind parameters were defined by Wind satellite data. ̉he planetary pattern of the auroral precipitation zones distribution for three events: on 10-11 January 1997, 21-22 October 2001 and 15 July 2000 was examined. The magnetic storms in these cases were driven by interplanetary magnetic clouds, Dst decreasing significantly during the storm main phase - to 80 nT, 150 nT and 300 nT, respectively. A typically long-lasting, steady depression of the Dst index was characteristic for these events. An analysis of the planetary distribution demonstrates that the width of auroral oval precipitation zones in the morning - evening sectors depends on the Dst index value and the latitudinal displacement of their boundaries is controlled by the AL index. It is shown that during long-lasting steadily depressed Dst index maximum shift of auroral precipitation boundaries occurs in the morning - evening sectors.

I.V. Despirak, Zh. V. Dashkevich, V. Guineva
Study of the auroral emissions during substorms connected with different solar wind streams
Abstract: Spistbergen photometer data from the 2005/2008 winter seasons have been used to study the variation of auroral 5577 A and 6300 A intensity ratio in different conditions of interplanetary medium and various geomagnetic activity. Solar wind and interplanetary magnetic field parameters were taken from CDAWeb (http://cdaweb.gsfc.nasa.gov/cdaweb/istp_public/). Using WIND satellite data for the examined periods, the different solar wind streams were revealed: recurrent streams from coronal magnetic holes and magnetic clouds connected with non-stationary processes at the Sun. Substorm onset time and further development were verified by ground-based data of IMAGE magnetometers network, MIRACLE system and by data of all-sky camera at Spistbergen. The auroral 5577 A and 6300 A intensity ratio was obtained for different auroral bulge locations - on the polar edge and inside the bulge. The particularities in behaviours of the emission intensities and the 6300/5577 ratio during substorms observed by solar wind recurrent streams and by magnetic clouds are discussed.

Guineva V., Despirak I., Werner R., Trondsen E., Honary F., Marple S., Dahle K., Stauning P.
THE AURORAL EMISSIONS AND THE ELECTRON PRECIPITATION UNDER DIFFERENT GEOMAGNETIC CONDITIONS DURING RECURRENT SOLAR WIND STREAM

Zbysek Mosna, Petra Sauli, K. Georgieva Ionospheric responses to the particular solar events

Katya Georgieva Planetary tides and solar activity

V.Guineva, G.Witt, J.Gumbel, M.Khaplanov, R.Werner, J.Hedin, S.Neichev, B.Kirov, L.Bankov, P.Gramatikov, V.Tashev, K.Hauglund, G.Hansen, J.Ilstad, H.Wold
ASLAF: Detector of the Direct Solar Lyman-Alpha Radiation. Future Alternatives