Using Lasers To Aim Man-Made Lightning

I have to admit that when I read this, my first reaction was “It's about time!”

For quite some time now scientists studying lightning have been able to trigger strikes using pulses from medium power lasers aimed into the sky. (The lasers ionize the air, creating a low resistance path for lightning to follow.) This new means follows the old method of using rockets trailing wires to achieve the same effect.

Now Army engineers are using the concept to channel man-made lightning bolts to destroy targets.

The Laser-Induced Plasma Channel, or LIPC, is designed to take out targets that conduct electricity better than the air or ground that surrounds them. How did the scientists harness the seemingly random path made by lightning bolts, and how does a laser help? To understand how the technology works, it helps to get a brief background on physics.


"If a laser beam is intense enough, its electro-magnetic field is strong enough to rip electrons off of air molecules, creating plasma," says [George]Fischer, [lead scientist on the project]. "This plasma is located along the path of the laser beam, so we can direct it wherever we want by moving a mirror."

"The plasma channel conducts electricity way better than un-ionized air, so if we set up the laser so that the filament comes near a high-voltage source, the electrical energy will travel down the filament," Fischer says.

A target, an enemy vehicle, or even some types of unexploded ordnance would be a better conductor than the ground it sits on. Since the voltage drop across the target would be the same as the voltage drop across the same distance of ground, current flows through the target. In the case of unexploded ordnance, it would detonate, explains Fischer.

Considering the efficiency of lasers converting electrical energy to light energy isn't all that great, using lasers to direct an electrical charge to a distant target would likely be far more efficient. The laser itself doesn't need to be large or powerful. It only needs enough power to generate a brief high-power pulse in order for the “lightning bolt” to hit its target.

One step closer to Star Trek.