May 24, 2021 13:00:00

Succeeded in accelerating light by 30% in plasma

The experimental results were announced that the speed of light in the plasma could be adjusted by irradiating the plasma with a powerful laser from two directions. Based on the results of this experiment, which clarified the interaction between high-temperature plasma and a powerful laser, it is expected that the

inertial confinement type fusion technology that causes nuclear fusion by turning fuel into plasma with a laser or the like will make great progress.

Phys. Rev. Lett. 126, 205001 (2021) --Slow and Fast Light in Plasma Using Optical Wave Mixing
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.205001

Physics --Light Pulses Change Speed in a Plasma
https://physics.aps.org/articles/v14/s60

Physicists Have Broken The Speed of Light With Pulses Inside Hot Plasma
https://www.sciencealert.com/pulses-of-light-can-break-the-universal-speed-limit-and-it-s-been-seen-inside-plasma

Albert Einstein, who established the special theory of relativity, called the speed of light traveling in a vacuum at a speed of about 300,000 km / s the 'ultimate speed limit', but the speed at which a pulse of light passes through a substance. Can be slower than or exceed the speed of light. Professor Clement Goyon, a researcher at Lawrence Livermore National Laboratory in the United States, who was pursuing the relationship between speed and substance called

group velocity, conducted an experiment to irradiate plasma with a laser and observe the situation. I did.

The research team first used a laser to ionize hydrogen and helium gas to generate plasma, which was then irradiated with a second laser. Then, when the speed of light at the intersection of the two lasers was measured, it was found that in the second laser light, the velocity component in the horizontal direction was decelerated according to the change in the refractive index of the plasma. .. It is said that this deceleration was caused by the interaction between the two lasers and plasma.

Furthermore, by changing the frequencies of the two lasers, the research team was able to adjust the speed of light traveling through the plasma from one-tenth to 1.3 times the speed of light in a vacuum.

In this experiment, speeds exceeding the speed of light were observed, but since this does not violate existing physical laws such as special relativity and the principle of invariant speed of light, superluminal flight and communication like SF It does not lead to the realization of. Nonetheless, the results of this research that we were able to adjust the characteristics of extremely powerful laser light with high-temperature plasma are the best, such as the improvement of fusion technology and the improvement of particle accelerators, which are considered to be the energy of dreams. It is said to bring various benefits to advanced technology.