Elena Grigorenko¹, Gina A DiBraccio², Lev Zelenyi¹, S. D. Shuvalov³, Vladimir Ermakov³, Helmi V Malova^1,4 and Edward Dubinin⁵, (1)Space Research Institute of Russian Academy of Science, Moscow, Russia, (2)University of Michigan, Ann Arbor, MI, United States, (3)Space Research Institute of the Russian Academy of Sciences (IKI), Moscow, Russia, (4)Scobeltsyn Institute of Nuclear Physics, Moscow, Russia, (5)Max-Planck-Institute for Solar System Research, Goettingen, Germany