Probing the nature of elementary particles and their interactions requires a lot of energy. For the past 20 years, physicists have sought an alternative to conventional particle colliders: plasma wakefield accelerators, which are theoretically thousands of times more powerful. But these were thought to be difficult to handle because plasma wakefields have many unstable features. “We started plasma acceleration work in the 1980s at the University of California, Los Angeles (UCLA) when most people doubted that a coherent accelerating structure could be established in a plasma,” says Chandrashekhar Joshi, Director of UCLA's Center for High Frequency Electronics.

In 1998, Joshi's UCLA team joined forces with scientists at the Stanford Linear Accelerator Center in Menlo Park, California, and the University of Southern California at Los Angeles.

“The specific aim of the collaboration was to take plasma-acceleration research to the next level,” says Joshi. Most recently, electric fields were used in plasmas to double the energy of electrons (see page 741). The method can generate ultra-powerful beams with narrow energy spread, invaluable for high-energy physics applications. “This work shows that plasma accelerators can produce the kind of energy that high-energy physicists really care about,” says Joshi.