CASA Seminar

Friday, November 15, 2002, 10:00 AM
ARC 231/233

Table-top Laser Driven Accelerator Research at LBNL

Wim Leemans

With the advent of high peak power ultra-short pulse laser systems, significant progress has been made on demonstrating the generation of multi-GV electric field gradients in plasmas and the trapping and acceleration of electrons in these fields to multi-MeV energies (> 100 MeV). By tightly focusing (5 - 10 micron) high power laser beams (multi-TW) into high density plasmas (> 1019 cm-3), high amounts of electrons per bunch (> 5 nC) have been accelerated in distances typically on the order of a mm, with beam divergence angles on the order of 10 mrad. However, due to the inherent lack of control in the present regime of laser wakefield acceleration experiments, beams with 100 % energy spread are produced. Despite this large "longitudinal" emittance, using high repetition rate lasers (10 Hz), nuclear activation experiments have been performed at the l’OASIS laboratory of the Center for Beam Physics, with gaseous targets, demonstrating that sufficiently high fluxes of high energy electron beams can now be produced. As a means of reducing the energy spread, experiments are underway on laser triggered electron trapping in the plasma waves through optical manipulation of plasma electrons by additional laser beams. To increase the net beam energy gain, development of optical guiding structures is being pursued to extend the acceleration distance from mm’s to cm’s. An overview will be given of the experimental system at l’OASIS lab, progress towards the controlled acceleration of electrons and applications of laser driven accelerators including coherent emission of far infrared radiation.

Talk Slides:   PowerPoint

(Coffee & Cookies before the seminar starting 9:30 AM)