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.

AURORAL PRECIPITATION DYNAMICS DURING THE MAGNETIC CLOUD PASSING O.I. Yagodkina, V.G. Vorobjev (Polar Geophysical Institute, Apatity, Murmansk region) Abstract. Characteristics of auroral precipitation during the magnetic storm driven by the magnetic cloud on December 11-12, 2004 were examined. Meridian scanning photometer observations at Barentsburg (BAB) and Lovozero (LOZ), and an interactive Auroral Precipitating Model (АРМ) were used to show the possibility of АРМ using for the description of the auroral luminosity features. Spectral characteristics of aurorae observed from MSP in the pre-noon and after-noon sectors showed that discrete forms were caused by precipitation of relatively soft electrons. In the after-noon auroral arcs were observed near the poleward edge of the red auroral band which was narrower than in the pre-noon and observed at latitudes from 73° to 77° CGL. “Physics o f Auroral Phenomena", Proc. XXXVI Annual Seminar, Apatity, pp. 21 - 24, 2013 C j T \ P o la r © Kola Science Centre, Russian Academy of Science, 2013 Institute8'031 1. Data used To investigate the auroral dynamics during magnetic storm on December 11-12, 2004 with intensity in Dst of about - 40 nT driven by the magnetic cloud the meridian scanning photometer (MSP) observations at Barentsburg (BAB, Ф'=75.2°; MLT=UT+2.5) and at Lovozero (LOZ, Ф'=64.2°; MLT=UT+2.5), and the interactive Auroral Precipitating Model (АРМ) parameterized by magnetic activity ( http://apm.pgia.ruZ ) were used. The observations of auroral intensity were made in 557.7 nm and 630.0 nm emissions channels by MSPs. The boundaries of auroral precipitation were examined from АРМ which yields a global distribution of electron precipitation in different precipitation zones. By using the model we obtained also the locations of BAB and LOZ relative to DAZ, AOP and SDP precipitation zones. This notation of precipitation was proposed by Starkov et al. (2002, 2003). DAZ (diffuse auroral zone) is the region of diffuse precipitation equatorward of auroral oval. AOP (auroral oval precipitation) is the region of structured precipitation. SDP (soft diffuse precipitation) is the region of soft diffuse precipitation poleward the AOP region. 2. Results Earlier, Vorobjev and Yagodkina (2005) compared pre- noon and pre-midnight precipitation features obtained by using АРМ during a magnetic storm on November 23-29, 1986, with a peak value of Dst being about - 100 nT, and verified that the positions of DAZ and AOP boundaries are reasonably consistent with the DMSP F7 spacecraft observations. Recently, Yagodkina et al. (2012) examined the dynamics of auroral precipitation boundaries in the dawn and the dusk sectors during three magnetic storms with Dst about -80, -200 and -300 nT by using АРМ and DMSP F I0-14 observations. They concluded that the model describes well enough the global distribution of the auroral precipitation and that model calculations are capable of filling the gaps in spacecraft observations, thereby providing a more complete picture of precipitation dynamics during magnetic storms. The main purpose of this study is to investigate the characteristics of auroral luminosity during the magnetic storm driven by the magnetic cloud and to illustrate possibility of the АРМ application for characterization o f the auroral luminosity boundaries. Magnetic storm on December 11-12, 2004 In Fig. 1 the solar wind plasma and IMF are shown. The magnetic storm was triggered by the sudden commencement on December 11 at 1400 UT when the cloud Sheath region, which is characterized by the high density, increased velocity and strong IMF variability, reached the magnetosphere. The Sheath is marked by vertical dashed lines in Fig. 1. Fig. 1 The solar wind plasma and IMF on Dec. 11-12, 2004 2 1 -6 0 0 AL.rtT •ЮОО e — 4 Bx.nT О ■124 . ; . ■ j. ■I ............................ 2 0 0 0 0 0 T.deo D e c e m b e r 1 1 D e c e m b e r 1 2