The goal here is to use high electric fields in plasmas to accelerate electrons to 100-GeV energies over distances of meters rather than kilometers. This should promote the development of new particle colliders and x-ray sources. The predicted high acceleration gradients in plasmas have been achieved in recent years, but could only be used with external electron injection from a conventional source. Now scientists at the University of Michigan (Donald Umstadter, 313-764-2284) have made progress in eliminating conventional electron sources altogether. In a preliminary experiment, by simply focusing a laser into a plasma, the Michigan scientists have extracted a collimated electron beam with multi-MeV energies and hope to have a beam of GeV electrons within a year. They also have a way of creating ultrashort bunches of electrons to make the highest quality electron beams (with much lower energy spread). First, they send a 100-fsec laser pulse into a gas, ionizing the gas and setting up a plasma wave. A second laser pulse, directed at right angles to the first, then induces nearby electrons to catch the plasma wave and ride with it synchronously to high energies.
Available at: http://works.bepress.com/donald_umstadter/68/