New Methods of Acceleration

The path to the goal of attainment of higher energies than currently possible in accelerators may well utilize entirely new methods for the production of strong electric accelerating fields. A variety of different approaches are currently being studied
 
 

 Contours of two-frequency laser intensity (left column) and the accelerating field of the plasma wave (right column) for three distances of propagation into the plasma from a 2-D particle-in-cell computer calculation.

UCLA Plasma Beat Wave Accelerator Program

The "proof-of-principle" plasma beat wave acceleration (PBWA) experiments at UCLA have shown electrons accelerated from an initial 2 MeV to 30 MeV over about 1 cm. The accelerating structure was extensively diagnosed but the injected electrons were essentially "test particles." The new NEPTUNE Laboratory for Advanced Accelerator Physics will use an upgraded laser to produce a 4 cm PBWA and a state-of-the-art RF photoinjector and linac for high quality 16 MeV beam injection. The objective of the experiment is to study the quality (phase space) of the plasma-accelerated 100 MeV output beam. One issue is phase velocity nonuniformity due to laser pulse distortion.

 

Laser Wakefields

A powerful (terawatt) laser beam, focused into a plasma jet at the University of Michigan, accelerates electrons to relativistic energies by means of a laser wakefield. The spatial profile (or transverse emittance) of the accelerated beam (shown by the green circle) is shown to be comparable to that produced by a conventional RF linac, but in an acceleration length that is over ten thousand times shorter.
This is the longitudinal wakefield in a hollow plasma channel excited by a short laser pulse. The flat top indicates the location of the hollow channel.