Waves are an interesting (and fun!) way to accelerate objects - just think of surfers at the beach being accelerated by ocean waves. The same concept can be used to accelerate electrons to very, very high energies, nearly the speed of light. An electron rides a wave just like a surfer rides a wave at the beach, falling down a potential hill. The wave the electron rides is produced by very short laser pulses propagating through a plasma. This form of acceleration is much more compact (and much cheaper) than conventional acceleration.