Researchers from the Pentagon's Non-Meteorological Weapons Directorate created a prototype of an acoustic cannon that uses laser radiation to generate loud sounds. As Defense One writes, the new weapon can create a source of loud sound anywhere in the world at a significant distance from itself.

The non-lethal acoustical weapon uses the power of sound to temporarily kill people. Today such weapons are used by the US military. It was developed in the second half of the 1990's and was named LRAD (Long Range Acoustic Device, long-range acoustic device).

The American acoustic cannon is capable of transmitting voice commands with an intensity of up to 150 decibels. This same weapon can be used as a loud sound generator with a frequency of two to three kilohertz, extremely unpleasant for human hearing. Acoustic guns are periodically used in the US to disperse uncontrolled protests.

In LRAD, small electromagnetic loudspeakers are used for sound transmission. These emitters are installed in the gun in such a way that their sound waves partially converge and they cause a phenomenon of resonance. Due to this, LRAD can form an acoustic beam with a divergence angle of 30 to 60 degrees.

The new acoustic gun, developed by the specialists of the Non-fatal Weapons Management Agency, uses femtosecond lasers capable of generating laser radiation by pulses several femtoseconds long.

In the new device, one of the generators is used to form a ball of plasma. It takes about 10-15 seconds to form it. Then the second generator sends a laser beam of a very narrow spectrum onto the plasma ball. As a result of the interaction of laser radiation with plasma, a bright glow and a loud sound.

The change in the frequency of the laser radiation acting on the plasma makes it possible to change the frequency of the sound produced. Researchers say that in the next three years they will be able to recreate the human voice with the help of laser and plasma.

The developers also argue that thanks to the use of lasers and mirrors, a new acoustic cannon can create a source of loud sound (a plasma area with laser acting on it) anywhere in the world at a distance of up to 30 kilometers from the installation. Other details about the new development are not disclosed.

The US Department of Defense released a short video test of the prototype laser acoustic gun. At the end of the recording, in particular, against the background of the squeak created by the device, a sound resembling the voice of a man is heard, uttering certain words.

Today, there are several types of non-lethal weapons. In the US, in addition to acoustic cannons, so-called "pain rays" are also used, also developed in the second half of the 1990s. This weapon is a microwave emitter and an antenna.

When a person hits a radiation system 83 percent of the energy of radiation is absorbed by his skin. In this case, the target experiences severe burning.

The installation operates in a wave band equal to 95 gigahertz. This radiation can not penetrate the human skin deeper than 0.4 millimeters. The effect of the "ray of pain" leads to instantaneous heating of the surface of the skin to 44 degrees Celsius. "Ray of Pain" was tested in Afghanistan and Iraq.

Source: nplus1.