On the 26th of May 2018, for the first time, electrons were accelerated by a wakefield generated by protons which zipped through a plasma. The AWAKE collaboration at CERN stays behind this achievement. If you want to read more about this, journal Nature published a paper today, and it describes the result. A factor of around 100 over a length of 10 meters accelerated the electrons, and after that, they got injected into AWAKE at about 19 MeV (million electron volts) energy, and it attained almost 2 GeV (billion electron volts) energy. Even though it is just the beginning of this development, if plasma wakefields are used they could reduce the costs and sizes of the accelerators that achieve high-energy collisions and are used by physicists to probe specific laws.
Advanced Wakefield Experiment, AWAKE, is an R&D project that investigates the concept described above. The accelerators at the end of the first paragraph use radio-frequency cavities as a particle beams kicker to higher energies. It alternates the electrical polarity of charged zones within the RF cavity combined with repulsion and attraction, and it accelerates the particles. Contrary to this, the wakefield ones accelerate the particles by surfing on top of the Wakefield which contains such charged zones as well.
This wakefields theory came into the game in the late 1970s and according to an AWAKE spokesperson, Allen Caldwell “Wakefield accelerators have two different beams: the beam of particles that is the target for the acceleration is known as a ‘witness beam’, while the beam that generates the Wakefield itself is known as the ‘drive beam’”
Other Wakefield examples used lasers or electrons to drive beam and AWAKE is the first one to use protons, the opportunity provided by CERN. The proton drive beams penetrate deeper into the plasma.