The US military are developing a new weapon which might soon be making science fiction enthusiasts’ dreams come true.
The device will shoot lightning bolts down laser beams to destroy its targets.
Laser and plasma weapons feature in a wide number of science fiction universes. The phasers of Star Trek and blasters used in Star Wars are both laser weapons. Plasma weapons feature in the Halo video game franchise and Transformers.
The Light-Induced Plasma Channel (LIPC) is designed to take out targets that conduct electricity better than the air or ground that surrounds them.
“If a laser puts out a pulse with modest energy, but the time is incredibly tiny, the power can be huge,” said George Fischer, lead scientist on the project. “During the duration of the laser pulse, it can be putting out more power than a large city needs, but the pulse only lasts for two-trillionths of a second.”
“For very powerful and high intensity laser pulses, the air can act like a lens, keeping the light in a small-diameter filament,” said Fischer. “We use an ultra-short-pulse laser of modest energy to make a laser beam so intense that it focuses on itself in air and stays focused in a filament.”
“If a laser beam is intense enough, its electro-magnetic field is strong enough to rip electrons off of air molecules, creating plasma,” said Fischer. “This plasma is located along the path of the laser beam, so we can direct it wherever we want by moving a mirror.”
The optical amplifier output is 50 billion watts of optical power, that is 500 million times more than the output from a 100 watt filament light bulb.
“Air is composed of neutral molecules and is an insulator,” Fischer said. When lightning from a thunderstorm leaps from cloud to ground, it behaves just as any other sources of electrical energy and follows the path of least resistance.
“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 said.
A target, for example a vehicle, 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.
Testing the weapon was apparently as cool as it sounds.
“We never got tired of the lightning bolts zapping our simulated (targets),” said Fischer.
A number of challenges must be overcome, however, before this technology can be used. There is a danger that it will light could focus in a glass lens, or in other parts of the laser amplifier system, which would destroy it. Other challenges included synchronizing the laser with the high voltage, ruggedizing the device to survive under the extreme environmental conditions of an operational environment, and powering the system for extended periods of time.