Plasma acceleration

A keel panel accelerator ( Accelerator Wakefield English ) is a particle, wherein said using a laser or electron beam or a charged proton wave is generated in a plasma path. Kiel field accelerators are the subject of current research, yet they are not permanently used in accelerator facilities (as of 2013). The way to do this is to be investigated in the next few years, among others, from the FACET project at SLAC, the LAOLA project at the German Electron Synchrotron (DESY ) and the AWAKE project at CERN. They could be built much more compact than other linear accelerator and could complement them in industry and medicine. A use in particle physics is investigated.

Comparison with other types of accelerators

In conventional particle accelerators, the electric field strength and thus the acceleration by the electric strength is limited. In order to achieve high energies, the acceleration sections therefore need to be used multiple times as in ring accelerators or be very numerous in linear accelerators. A keel -field accelerator circumvents this limitation: He uses a plasma in which a laser or a particle beam, a plasma wave is excited, prevail in the high electric field strengths. This wave travels at nearly the speed of light by the plasma. A correspondingly faster particle can therefore like a surfer riding on this wave and is continuously accelerated. Thus, the energy of particles over a distance of 1 cm to 1 GeV and a distance of 1 m can be increased to 50 GeV in experiments. Other types of accelerators need for 1 GeV distances of 30 meters and more. In addition to the maximum power is important, that the energy of the accelerated particles as uniformly as possible and the beam is well focused.

Principle of operation

These negatively charged electrons you shoot a very short electron beam in a plasma, so repel the electrons of the plasma and attract the positively charged ions. Behind the beam there arises a positively charged region that attracts the electrons previously repelled again. They grow back, so that the region is negatively charged and therefore repel each other again. This process is done several times with decreasing intensity, so that a wave propagates through the plasma regions of positive and negative charge. There is in each case a strong electric field in which the particles are accelerated to be accelerated between the areas.

With a proton beam produced in the same way a wave, here the electrons are first grown rather than repelled. Since the energy transfer to the beam to be accelerated depends on the energy of the wave- generating beam and protons can be accommodated more easily than electrons to high energies, one can accelerate electrons to very high energies in this way may be. A similar experiment ( " AWAKE " ) is currently being planned at CERN and is to be built by 2016. Protons can easily bring to high energies due to their higher mass, since they emit synchrotron in less synchrotron radiation. With a box keel accelerator, this high power is then to be transmitted to electrons.

A photon beam from a laser can be used. This drives many of especially the electrons, thus acts like an electron.

Thus, the accelerated beam remains permanently in the range of optimum acceleration, its speed must be close and must not change during the passage too much on the speed of the wave. Therefore, protons can be with a keel -field accelerator only accelerate if they already have a high energy and therefore its speed is already close to the speed of light. Electrons reach the necessary speed much faster, due to their small mass and can therefore also be obtained from the plasma itself.