Lasers Can Guide Dangerous Lightning Strikes to Safer Paths

This article has a key explanation:

“ The laser diverts lightning bolts by creating an easier path for the electrical discharge to flow down. When laser pulses are fired into the sky, a change in the refractive index of the air makes them shrink and become so intense that they ionise air molecules around them. This leads to a long chain of what the researchers call filaments in the sky, where air molecules rapidly heat up and race away at supersonic speeds, leaving a channel of low density, ionised air. These channels, which last for milliseconds, are more electrically conductive than the surrounding air, and so form an easier path for the lightning to follow.”

https://amp.theguardian.com/science/2023/jan/16/scientists-s...

https://archive.ph/7LC50

Also the opposite.

this can be used for tremendous evil if it hasnt already.

How do they make sure they don’t blind aircraft?

Good question:

“ The laser is powerful enough to be a risk to the eyes of overflying pilots, and during the experiments air traffic was closed over the test site. But the scientists believe the technology could still be useful, as launchpads and airports often have designated areas where no-fly restrictions apply. “It’s important to consider this aspect of safety,” said Houard.”

They might be assuming that aircraft will already be avoiding areas with powerful thunderstorms. Still, I'd assume a $2B laser goes a long way; you'd have to be pretty clear to pilots about where the danger zone is.