Experimental study of wakefields driven by a self-modulating proton bunch in plasma
Physical Review Accelerators and Beams American Physical Society 23:8 (2020) 81302
Abstract:
We study experimentally the longitudinal and transverse wakefields driven by a highly relativistic proton bunch during self-modulation in plasma. We show that the wakefields’ growth and amplitude increase with increasing seed amplitude as well as with the proton bunch charge in the plasma. We study transverse wakefields using the maximum radius of the proton bunch distribution measured on a screen downstream from the plasma. We study longitudinal wakefields by externally injecting electrons and measuring their final energy. Measurements agree with trends predicted by theory and numerical simulations and validate our understanding of the development of self-modulation. Experiments were performed in the context of the Advanced Wakefield Experiment (AWAKE).Numerical modelling of chromatic effects on axicon-focused beams used to generate HOFI plasma channels
Journal of Physics: Conference Series IOP Publishing 1596 (2020)
Abstract:
Hydrodynamic optical-field-ionised (HOFI) plasma channels promise a route towards high repetition-rate, metre-scale stages for future laser plasma accelerators. These channels are formed by hydrodynamic expansion of a plasma column produced by optical field ionisation at the focus of a laser, typically from an axicon lens. Since the laser pulses used to generate the initial plasma column are of sub-picosecond duration, chromatic effects in the axicon lens could be important. In this paper we assess these effects using a numerical propagation code. The code is validated using analytical formulae and experimental data. For the parameter range investigated, dispersive effects are found to be of minor importance, reducing the peak on-axis intensity in the focal region by approximately 10%.Evolution of a plasma column measured through modulation of a high-energy proton beam
ArXiv 2006.09991 (2020)
Guiding of high-intensity laser pulses in 100mm-long hydrodynamic optical-field-ionized plasma channels
(2020)
Nonlinear plasma wavelength scalings in a laser wakefield accelerator
Physical Review E American Physical Society 101:2 (2020) 23209