There's a lightning strike hike in strong solar wind

http://www.newscientist.com/article/dn25569-theres-a-lightning-strike-hike-in-strong-solar-wind.html#.U-vZLKOK3qw

15 May 2014 by Jacob Aron

Sparks fly when the solar wind blows. Charged particles emitted by the sun seem to be able to influence the rate of lightning strikes here on Earth, hints a new analysis.

By all accounts, lightning should be impossible. Air is an electrical insulator, so getting it to conduct current requires an incredibly intense electrical field. The puzzle is that observations of thunderstorms show that their fields are much too weak for bolts to fly, says Christopher Scott at the University of Reading, UK.

One idea is that high-energy particles from outer space called cosmic rays might provide the necessary boost. When incoming particles collide with air molecules, they set electrons loose and ionise the air, creating a cascade that lets current flow.

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That's not to say solar particles will turn a calm day into lightning-fuelled misery, because storm conditions already have to be in place to spark lightning.

"The effects of solar wind are limited, if this paper is true, to making lightning happen more often, providing conditions are already conducive to lightning," says Christopher Emersic at the University of Manchester, UK.