[1] Univ Colorado, Ctr Integrated Plasma Studies, Dept Phys, Boulder, CO 80309 USA
[2] Univ Maryland, IREAP, College Pk, MD 20742 USA
[3] Univ Maryland, IPST, College Pk, MD 20742 USA
[4] Kyung Hee Univ, Sch Space Res, Seoul, South Korea
[5] MTL, Belmont, MA USA
[6] Univ Maryland, Dept Phys, College Pk, MD 20742 USA