  Longitudinal space charge (LSC) effects are generally considered harmful in
free-electron lasers as they can seed unfavorable energy modulations that can
result in density modulations with associated emittance dilution. It was
pointed out, however, that such "micro-bunching instabilities" could be
potentially useful to support the generation of broadband coherent radiation.
Therefore there has been an increasing interest in devising accelerator beam
lines capable of controlling LSC induced density modulations. In the present
paper we augment these previous investigations by combining a grid-less space
charge algorithm with the popular particle-tracking program Elegant. This
high-fidelity model of the space charge is used to benchmark conventional LSC
models. We finally employ the developed model to optimize the performance of a
cascaded longitudinal space charge amplifier using beam parameters comparable
to the ones achievable at Fermilab Accelerator Science & Technology (FAST)
facility currently under commissioning at Fermilab.
