Presentation on theme: "THE AURORAL EMISSIONS AND THE ELECTRON PRECIPITATION UNDER DIFFERENT GEOMAGNETIC CONDITIONS DURING RECURRENT SOLAR WIND STREAM Guineva V. 1, Despirak I."— Presentation transcript:
THE AURORAL EMISSIONS AND THE ELECTRON PRECIPITATION UNDER DIFFERENT GEOMAGNETIC CONDITIONS DURING RECURRENT SOLAR WIND STREAM Guineva V. 1, Despirak I. 2, Werner R., Trondsen E. 3, Honary F. 4, Marple S. 4, Dahle K. 5, Stauning P. 6 1)Solar-Terrestrial Influences Laboratory, Bulgarian Academy of Sciences, Stara Zagora Department, 6000 Stara Zagora, P.O.Box 73, Bulgaria 2)Polar Geophysical Institute, Apatity, Russia 3)University of Oslo, Department of Physics, Norway 4)Lancaster University, Department of Communications Systems, UK 5)Andøya Rocket Range, Andenes, Norway 6)Danish Meteorological Institute, Copenhagen, Denmark
Observation instruments All-Sky Imager (ASI): ARR, Andenes, Norway (69.3°N, 16.03°E); 5577 Å and 6300 Å emissions; 10 s time resolution; 180° field of view in a 512x512 matrix; All-Sky Imager (ASI): Auroral Observatory, Longyearbyen, Svalbard (78.20°N, 15.83°E); Andenes Imaging Riometer for Ionospheric Studies (AIRIS): absorption of cosmic noise at 38.2 MHz by 49 beams (7x7 area) every second (electrons with energies 10÷x100keV and deposition heights centered at about 90 km); Imaging Riometer for Ionospheric Studies (IRIS): Kilpisjärvi, Finland (69.05°N, 20.79°E); 64-beam Imaging Riometer and magnetometer at Longyearbyen, 38.2 MHz absorption; Andenes Magnetometer: registers the magnetic field components every second. Simultaneous observations from several instruments are used:
Projected fields of view of ASI and IRIS Instruments projected fields of view: Longyearbyen All-Sky Imager 6300Å (emission altitude 250 km) 5577Å (emission altitude 120 km) Andenes All-Sky Imager 6300Å (emission altitude 250 km) 5577Å (emission altitude 120 km) Andenes Imaging Riometer (AIRIS) (90 km reference altitude) Imaging Riometer at Kilpisjärvi (IRIS) (90 km altitude) Imaging Riometer at Longyearbyen (90 km altitude)
Examined periods during 2005/2006 season – the most disturbed days in November (D1 and D2); – quiet period; – most disturbed day in the month (D1), all instruments had functioned
IMF, solar wind parameters
Temporal development ASI keograms along the 103.8°E geomagnetic meridian IRIS keograms along the 103.8°E geomagnetic meridian, 65.2°-66.8°MLAT IRIS absorption beam 25 at 38.2 MHz Total magnetic field and its H, Z and D components at Andenes 6300 Å 65°-74.2° MLAT 5577 Å 68.8°-72° MLAT :50-5:40 UT :30-5:50 UT
Spatial distributions of the emissions and particles UT UT UT 1 min. interval images 5577Å 6300Å Kilpisjärvi IRIS absorption images Andøya all-sky images
UTCorrelation between:Zone IZone IIZone III 18:00 – 21: I 5577 Å-I 6300 ÅCentral point Mean value I 5577 Å - Absorption I 6300 Å - Absorption :00 – 24: I 5577 Å-I 6300 ÅCentral point Mean value I 5577 Å - Absorption I 6300 Å - Absorption IIIIII I II III IIIIII III
UTMean ratios:Zone IZone IIZone III 18:00 – 21: I 6300 Å/I 5577 ÅCentral point Mean value Absorption/I 5577 Å Absorption/I 6300 Å :00 – 24: I 6300 Å/I 5577 ÅCentral point Mean value Absorption/I 5577 Å Absorption/I 6300 Å I I II III
UTCorrelation between I 5577 Å- I 6300 Å: 18:00 – 21: Central point0.8 Mean value :00 – 24: Central point0.749 Mean value0.752
UTMean ratios: 18:00 – 21: I 6300 Å/I 5577 ÅCentral point0.508 Mean value0.56 Absorption/I 5577 Å0.147 Absorption/I 6300 Å :00 – 24: I 6300 Å/I 5577 ÅCentral point0.365 Mean value0.41 Absorption/I 5577 Å0.343 Absorption/I 6300 Å0.063
Summary The behaviour of the 5577 Å and 6300 Å intensities and the absorption at 38.2 MHz in some cases under different conditions – during substorms and under quiet conditions, during the passage of recurrent high energy solar wind stream is examined; During substorms, the energy spectrum of the precipitating particles is enhanced in the part of the higher energies; I 6300 /I 5577 becomes times smaller during substorms (~0.2) than in quiet conditions (~ ); I 6300 and I 5577 correlate very well regardless of the conditions.
Acknowledgments: The work was supported by the European Union’s 6th Framework Program within the ALOMAR eARI (22_VeGi and 40_VeGi) Projects. We are thankful for the data originated from the Imaging Riometer for ionospheric Studies (IRIS), operated by the Department of Communications Systems at Lancaster University (UK) in collaboration with the Sodankylä Geophysical Observatory, and funded by the Particle Physics and Astronomy Research Council (PPARC). The authors are grateful to Truls Lynne Hansen of the Tromsø Geophysical Observatory, University of Tromsø, Norway, for providing magnetometer data. We thank to Kjell Henriksen Observatory and Danish Meteorological Institute for giving us the data from the 64-beam imaging riometer and the magnetometer at Longyearbyen.