Software Open Access
Simulations made with PIConGPU in 2d geometry with a longitudinally modified gaussian laser on a foil.
The laser has been modified to reproduce the main features of the pulse shape seen in the experiments as a result of modifying TOD and GVD.
The three main features, which were enabled with varying strength in the simulations:
- an exponential ramp on the timescale of 300fs before the gaussian main pulse
- a postpulse with around 100fs delay and around 0.2 of the total pulse energy
- a skewness of the gaussian - modelled by two gaussian halves for the rising and falling part
From the spectra of the accelerated protons the cutoff energy is measured. The main result is, that the variations of the spectra are much smaller than those observed in the experiments, suggesting more complex mechanisms than those modelled here.