Enhanced energetic electron fluxes at the region of the auroral oval during quiet geomagnetic conditions November 2009 M.O. Riazantseva a,b,⇑ , I.N. Myagkova a , M.V. Karavaev a , E.E. Antonova a,b , I.L. Ovchinnikov a , B.V. Marjin a , M.A. Saveliev c , V.M. Feigin c , M.V. Stepanova d a Skobeltsyn Institute of Nuclear Physics, MSU, Leninskie gory, GSP-1, 11999 Moscow, Russia b Space Research Institute RAS, Moscow, Russia c Russian Space Agency, Moscow, Russia d Universidad de Santiago de Chile (USACH), Chile Received 13 November 2011; received in revised form 15 April 2012; accepted 21 May 2012 Available online 29 May 2012 Abstract Enhanced fluxes of subrelativistic electrons were studied using the CORONAS-PHOTON satellite data during November 2009. Dur- ing this time interval quiet geomagnetic conditions were unusually quiet. It was found that for more than 50% of all events, the enhanced fluxes with very similar characteristics were observed at two or more consecutive orbits, i.e. have a life time of a few hours. The analysis of relative location of enhanced fluxes and auroral particle precipitations, measured simultaneously by the low orbiting METEOR-M and DMSP satellites, showed that the enhanced fluxes are located inside the auroral oval, i.e. poleward from the external boundary of the outer electron radiation belt. This fact was also confirmed comparing these fluxes with the auroral oval boundaries provided by the OVATION model of auroral precipitations. The nature of the observed events is discussed. Ó 2012 COSPAR. Published by Elsevier Ltd. All rights reserved. Keywords: Low orbiting satellite measurements; Subrelativistic electrons; Outer radiation belt; Auroral particle precipitations 1. Introduction Enhanced subrelativistic electron fluxes have sporadi- cally been observed in the plasma sheet during more than 40 years. Anderson et al. (1965) named these fluxes ‘island fluxes’ and showed that they are most commonly observed at low magnetic latitudes in the magnetotail. Later, Bame et al. (1967), Meng and Anderson (1971) showed that they are located inside the plasma sheet. Posterior studies showed that enhanced energetic particle fluxes have a clear dawn-dusk asymmetry: the ion fluxes exceed the electron fluxes in the dusk-side, and vice versa, the electron fluxes are dominant in the dawn side (see Sarafopoulos et al. (2001) and references therein). Burin des Roziers et al. (2009a) showed that strong energetic electron fluxes in the plasma sheet exist during a wide range of geomagnetic activity. Although most of extreme events were observed during enhanced geomagnetic activity, rapid variations in the energetic electron fluxes were also detected during quiet geomagnetic conditions. Despite a significant number of theoretical works, the nature of sporadic appearance of enhanced energetic elec- tron fluxes in the plasma sheet remains unclear (see A ˚ snes et al. (2008) and references therein). It is not even clear whether we deal mainly with a spatial or a temporal phe- nomenon. This is because a high-altitude satellite, able to 0273-1177/$36.00 Ó 2012 COSPAR. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.asr.2012.05.015 ⇑ Corresponding author at: Skobeltsyn Institute of Nuclear Physics, MSU, Leninskie gory, GSP-1, 11999 Moscow, Russia. Tel.: +7 495 9392810; fax: +7 495 9390896. E-mail addresses: orearm@gmail.com (M.O. Riazantseva), irina@srd. sinp.msu.ru (I.N. Myagkova), michael23j@mail.ru (M.V. Karavaev), antonova@orearm.msk.ru (E.E. Antonova), ilya@prao.ru (I.L. Ovchinnikov), sava@ntsomz.ru (M.A. Saveliev), feigin@ntsomz.ru (V.M. Feigin), marinastepanova@vtr.net (M.V. Stepanova). www.elsevier.com/locate/asr Available online at www.sciencedirect.com Advances in Space Research 50 (2012) 623–631