[1] IZMIRAN, Solar Phys Div, Troitsk 142090, Moscow Region, Russia
[2] Russian Acad Sci, Inst Solar Terr Phys, SD, Irkutsk 664033, Russia
[3] Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA
[4] Lockheed Martin Solar & Astrophys Lab, Palo Alto, CA 94304 USA