Plasma electron acceleration driven by a long-wave-infrared laser.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38740793.
- Also identified by DOI 10.1038/s41467-024-48413-y and PMC identifier 11519596.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Laser-driven plasma accelerators provide tabletop sources of relativistic electron bunches and femtosecond x-ray pulses, but usually require petawatt-class solid-state-laser pulses of wavelength λ<sub>L</sub> ~ 1 μm. Longer-λ<sub>L</sub> lasers can potentially accelerate higher-quality bunches, since they require less power to drive larger wakes in less dense plasma. Here, we report on a self-injecting plasma accelerator driven by a long-wave-infrared laser: a chirped-pulse-amplified CO<sub>2</sub> laser (λ<sub>L</sub> ≈ 10 μm). Through optical scattering experiments, we observed wakes that 4-ps CO<sub>2</sub> pulses with < 1/2 terawatt (TW) peak power drove in hydrogen plasma of electron density down to 4 × 10<sup>17</sup> cm<sup>-3</sup> (1/100 atmospheric density) via a self-modulation (SM) instability. Shorter, more powerful CO<sub>2</sub> pulses drove wakes in plasma down to 3 × 10<sup>16</sup> cm<sup>-3</sup> that captured and accelerated plasma electrons to relativistic energy. Collimated quasi-monoenergetic features in the electron output marked the onset of a transition from SM to bubble-regime acceleration, portending future higher-quality accelerators driven by yet shorter, more powerful pulses.