This electricity girl from To Aru no Majutsu no Index anime series is Mikoto Misaka, she is the main heroin in the series, she was able to control and create electricity, she can shock you, she can hack into computer networks and scurity system, create a Chain-Sword whip made of iron particles and also she can fire a metal projectile as destructive coins at high speeds.
I still don't get the Cosplayer name is in this Cool Misaka Makoto Cosplay picture, but whoever she is, she has to made Misaka Mikoto looks very cool here, I give her 100 for her pose and everything looks cool with a blue touch, actually I want to see angry Misaka Mikoto Cosplay when she make a thunder storm that causes citywide blackouts.