Generation of radio frequency radiation by femtosecond filaments.

Garrett, Travis; Elle, Jennifer; White, Michael; Reid, Remington; Englesbe, Alexander; Phillips, Ryan; Mardahl, Peter; Thornton, Erin et al. · Phys Rev E · 2021

basic_science · Level V

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Abstract

Recent experiments have shown that femtosecond filamentation plasmas generate ultrabroadband radio frequency radiation (RF). We show that a combination of plasma dynamics is responsible for the RF: A plasma wake field develops behind the laser pulse, and this wake excites (and copropagates with) a surface wave on the plasma column. The surface wave proceeds to detach from the end of the plasma and propagates forward as the RF pulse. We have developed a four-stage model of these plasma wake surface waves and find that it accurately predicts the RF from a wide range of experiments, including both 800-nm and 3.9-μm laser systems.