We don't hesitate to show excitement over non lethal and less-than-lethal weapons, but the reality is that they're kinda scary. In particular when we're starting to see hand-held heat weapons which leave little to no trace of ever being used.
A long time ago we heard about the UK considering testing out some non lethal directed energy gear. Basically a beam-based weapon which would cause a burning sensation to discourage a victim (or attacker), but not actually damage skin or leave burn marks. This is what the Joint Non-Lethal Weapons Directorate, JNLWD, has been exploring since 2005. But according to project engineer Wesley Burgei, they've still got a few bugs left to work out:
"We have established the minimum irradiance to cause a sensation and have characterised where thermal injury begins," he says. "But the exact operating irradiance which balances a useful military effect with a conservative margin of safety has not been nailed down yet."
In plain words? There are some itty bitty safety issues. Thankfully those will be ironed out before the weapons ever hit the streets due to some UN protocol on blinding laser weapons. It turns out that they forbid weapons which would penetrate the retina and cause blindness. It seems odd that a beam-based weapon could affect skin without damaging eyesight, but, according to Burgei, it's entirely possible to use a "retina safe" wavelength.
It's great that safety is a priority in the design and creation of these beam-based weapons, but Steve Wright, a non lethal weapons analyst at Leeds Metropolitan University, raises an interesting point about them:
"Persuading by pain rather than brain - through conversation - has led to push-button torture in the past. If it leaves no mark on the skin how will anyone prove it's been abused?"
Tasers and the like leave evidence, marks and traces of use, but once they're within proper safety limitations, beam-based weapons like the one being built by the JNLWD won't. Not to start the "Oh, no! They'll be abused!" train, but how will we regulate them? [New Scientist]