Browsing by Subject "Laser wakefields"

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    Self-modulated laser wakefields driven by a CO₂ laser
    (2019-08) Welch, James Roland; Downer, Michael Coffin; Keto, John; Ditmire , Todd; Belkin, Mikhail
    Long-wavelength lasers are being explored for use in multi-stage laser wakefield accelerators with the eventual goal of creating a TeV-scale lepton collider. We use a high-power, ultrafast CO₂ laser (5 J, 4 ps, 10.6 μm) to generate self-modulated laser wakefields in a hydrogen gas jet, the first such experiment in this regime to our knowledge. Collective Thomson scattering (CTS) co-propagating probes were used to measure the plasma density in the gas jet and estimate the wakefield amplitudes. The measured wakefield have similar amplitudes to previous self-modulated laser wakefield experiments which measured accelerated electrons. The effects of gas jet geometry on the measured wavelength shift of the CTS probes were explored in depth, demonstrating a complex interplay of self-focusing and divergence effects based on the local plasma density and the pulse power.