The UCLA/NICADD plasma density transition trapping experiment

Abstract

Plasma density transition trapping is a recently purposed self-injection scheme for plasma wake-field accelerators. This technique uses a sharp downward plasma density transition to trap and accelerate background plasma electrons in a plasma wake-field. Two and three dimensional Particle-In-Cell (PIC) simulations show that electron beams of substantial charge can be captured using this technique, and that the beam parameters such as emittance, energy spread, and brightness can be optimized by manipulating the plasma density profile. These simulations also predict that transition trapping can produce beams with brightness > 5 /spl times/ 10/sup 14/ Amp/(m-rad)/sup 2/ when scaled to high plasma density regimes. A proof-of-principle plasma density transition trapping experiment is planned for the near future. This experiment is a collaboration between UCLA and Northern Illinois University (MCADD). The goal of the experiment is to capture a /spl sim/ 100 pC, 1.2 MeV beam with /spl sim/ 4% rms energy spread out of a 2 /spl times/ 10/sup 1/3 cm/sup -3/ peak density plasma using a /spl sim/ 6 nC, 14 MeV drive beam. Status and progress on the experiment are reported.