Modulational instability in large-amplitude linear laser wakefields

Abstract

We investigate the growth of ion density perturbations in large-amplitude linear laser wakefields via two-dimensional particle-in-cell simulations. Growth rates and wave numbers are found to be consistent with a longitudinal strong-field modulational instability (SFMI). We examine the transverse dependence of the instability for a Gaussian wakefield envelope and show that growth rates and wavenumbers can be maximised off-axis. On-axis growth rates are found to decrease with increasing ion mass or electron temperature. These results are in close agreement with the dispersion relation of a Langmuir wave with energy density that is large compared to the plasma thermal energy density. The implications for wakefield accelerators, in particular multi-pulse schemes, are discussed.

arXiv comment6 pages, 4 figures

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• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• SMILEI: a collaborative, open-source, multi-purpose particle-in-cell code for plasma simulation
• The ion motion in self-modulated plasma wakefield accelerators
• Excitation and Control of Plasma Wakefields by Multiple Laser Pulses
• Multi-Pulse Laser Wakefield Acceleration: A New Route to Efficient, High-Repetition-Rate Plasma Accelerators and High Flux Radiation Sources

Cited by in corpus (1)

• Measurement of the decay of laser-driven linear plasma wakefields