Accelerating
in the Future: Lasers Start to Produce
Quality
High Energy Electron Beams
Twenty-five years ago, a new
method was proposed for the acceleration of electrons to high energies using
lasers. The simplest implementation of a so-called laser wakefield accelerator
involves sending an intense laser pulse through a gas to ionize it and form a
plasma of dissociated electrons and ions. The radiation pressure of the laser
pushes the plasma electrons aside, creating a density modulation, or
‘wake.’ This changing electron density
can result in fields that accelerate particles thousands of times more strongly
than in conventional machines, accelerating electrons to high energies in short
distances. The compactness
of these accelerators would allow higher energies for the frontiers of
fundamental physics and make clinical and laboratory applications of
accelerators practical. In work that
brings the promise of laser-driven particle accelerators dramatically closer to
reality, we have produced high-quality electron beams in a plasma channel based
accelerating structure akin to an optical fiber of only a few millimeters long.