Summary report of working group 1: Laser-plasma wakefield acceleration

Abstract

Abstract. The work presented in the laser-plasma acceleration working group at the 2016 Advanced Accelerator Concepts (AAC) Workshop is summarized. Some of the highlights include: direct visualization of the electric and magnetic fields using a LPA (laser plasma accelerator) electron probe, offering transverse snapshots of the wakefield even for very low density; first demonstration of multi-pulse LPA and wakefield cancellation with a trailing pulse (first step to energy recovery); and control over the shock front angle to optimize density transition injection, which provides stable and low-energy-spread beams that are critical for increasing the efficiency of the recently presented staged LPA. Interesting ongoing and future work discussed included LPAs driven by CO 2 lasers and scaling to 10 GeV with and without optical guiding. Further details on each of these topics can be found in the respective papers in these Proceedings.

Two-dimensional structures of electron bunches in relativistic plasma cavities

“…Two promising methods to control the beam load formation are the density down-ramp and the ionization injection technique. Both methods produce witness electron beams with sub-fs temporal duration, a very high peak current of several kA, energy spreads well below 1% and an excellent transverse emittance [11][12][13][14][15][16]. The density down-ramp injection is reached by a longitudinal modulation of the plasma density with potentially ex- * Electronic address: lars.reichwein@hhu.de tremely large gradients (also known as shock-fronts) [17][18][19][20].…”

The filamented electron bunch of the bubble regime

“…The currently most promising methods are the ionization injection and the density down-ramp. Both methods produce electron beams with sub-fs duration, high peak currents in the range of several kA, energy spreads well below 1% and excellent transverse emittances [9][10][11][12][13]. Density-down ramp is achieved by longitudinally modulating the plasma density with extremely large gradients [14][15][16][17].…”

Fixing E-field divergence in strongly non-linear wakefields in homogeneous plasma

“…A promising method to control beam loading is the ionization injection technique. This method produces electron beams with sub-fs temporal duration, a very high peak current (several kA), energy spreads well below 1% for beams with energies in the multi-GeV range and an excellent transverse emittance (tens of nm rad) [11,[18][19][20][21][22]. The ionization injection requires a small amount of higher-Z gas, added to the gas used for acceleration [23,24].…”