Helmholtz Virtual Institute on Plasma Acceleration

Eckhard Elsen

Brian Foster

Excerpt from the DESY inFORM July/August 2011:

The so-called plasma wakefield acceleration has the potential to accelerate particles to highest energies over very short distances, thus offering a promising technology for future accelerator applications. The Helmholtz Association now decided on funding a virtual institute at DESY to do basic research to explore the possibilities of using the extremely high electric fields created in a plasma to reliably accelerate high-energy electrons. In a plasma, a highly excited state of ionised matter, electrons move freely between the atomic nuclei and produce enormous electrical fields – ideal to accelerate charged particles. The problem is that it is necessary to shoot a particle bunch into the plasma at exactly the right time when it is accelerated; an experiment which so far has not been carried out successfully. This is one of the topics of the new virtual institute which involves the University of Hamburg, Max Planck Institute in Munich, John Adams Institute (Great Britain), as well as the accelerator centres SLAC, LBNL (both USA) and CERN. In various experimental setups, the scientists will inject the electron beam of the FLASHII accelerator into a plasma cell, thereby further accelerating it with the plasma. “With FLASH, we have the ideal facility to make a big step forward with this kind of research,” says Brian Foster, spokesman of the virtual institute. “However, we want to reliably accelerate not only single electrons but the whole bunch. To achieve this, we still have to put a lot of effort into our beam diagnostics – to synchronise the plasma and electron beam, femtoseconds make the difference.” For their cooperative work in the virtual institute and for the acquisition of appropriate measuring instruments, the scientists applied funds of 3 million euros. For the five-year funding period, they plan several experiments which go hand in hand with the construction of the FLASHII beamline.