P237: Parallel simulation of complex waveforms in traveling-wave-tube amplifiers

We present our progress on a framework for efficient computer simulation of complex time-dependent waveforms (i.e. wideband, with large number of Fourier components) on massively parallel computer platforms. It is based on the parametric multi-frequency large-signal code CHRISTINE and relies on an adaptive algorithm for signal splitting and splicing in the time domain. Included in the model are memory effects, such as dispersion and wave reflections. The latter are resolved via a new accelerated iterative algorithm based on a quasi-Newton method for solving nonlinear multi-dimensional fixed-point problems. We validate our approach on such complex waveforms by operating the simulation kernel in the large-signal, nonlinear regime and comparing against the output of the benchmarked serial version. We introduce a hierarchy of relevant metrics to measure the amplifier's distortion using nonlinear optimization models.