Enhanced hot electron generation from liquid jets in moderate intensity laser–plasma interactions

We report the generation of MeV temperature electrons using sub-terawatt laser systems with a liquid methanol jet as a target. Remarkably, even at laser intensities of ∼1016 W/cm2, liquid cylindrical (size limited in 2 dimensions) 15 μm methanol jets produce electrons with temperatures of ∼1 MeV. Hot electron emission characteristics are strikingly similar to those observed in spherical microdroplet (size limited in 2 dimensions) targets. These results validate that modelling such experiments using 2D particle-in-cell simulations is not a compromising approximation. This work further simplifies the experimental complexities toward a multi-KHz highly regenerative source of directed multi-MeV electrons (and associated x rays and ions), demanding laser intensities 100× lower than conventional laser plasma sources. The findings also promise increased source energy and pointing stability, crucial for imaging or radiographic applications from such sources.