This particle boost technology uses laser light pulses that produce plasma waves, which, in turn, produce electromagnetic fields thousands of times stronger than the fields created by the radio frequency resonators of large accelerators such as the Large Hadron Collider. And charged particles, like surfers on the crest of a wave, accelerate to very high energies, having covered a distance of several tens of centimeters.
For comparison, we indicate that the particle acceleration rate in the 27-kilometer tunnel of the Large Hadron Collider is approximately 5 million volts per meter. In the worst case, plasma acceleration technology provides about 200 million volts per meter.
As an accelerator, a sapphire tube filled with a gas is used, the atoms of which are brought into an excited state and form a plasma using an applied electric potential. And shock plasma waves are generated by laser light, which is aimed at the central part of the tube and the effect of which leads to a kind of microexplosion at the focal point of the laser beam.
Microexplosions, constantly energized by the energy of subsequent laser pulses, form waves in the plasma that trap free electrons in their trap, accelerate them and send them to the tube in the form of a high-energy beam.
During the previous “record” experiment in 2014, during which the energy of 4.2 GeV was obtained, the uneven distribution of the plasma density in the channel led to the fact that the focus of the laser beam passing through the center of the plasma channel was lost, which caused damage to the sapphire tube. Now, researchers have improved this technology by using the light of a second laser, which acts as a stabilizer of plasma waves.
In the course of the following experiments, scientists plan to get a greater level of control over the process of injection of free electrons into a plasma wave, which will allow many times to increase the quality of the output electron beam. After that, an attempt will be made to combine several stages of electron acceleration into one longer process, which will allow to obtain electrons with even greater energy at the output.