biostudies-literatureStreeter MJVRCUK | Engineering and Physical Sciences Research Council (EPSRC)1004https://www.ebi.ac.uk/biostudies/studies/S-EPMC11759682biostudies-literatureUnknown16(1)Laser-plasma acceleration of protons offers a compact, ultra-fast alternative to conventional acceleration techniques, and is being widely pursued for potential applications in medicine, industry and fundamental science. Creating a stable, collimated beam of protons at high repetition rates presents a key challenge. Here, we demonstrate the generation of multi-MeV proton beams from a fast-replenishing ambient-temperature liquid sheet. The beam has an unprecedentedly low divergence of 1° (≤20 mrad), resulting from magnetic self-guiding of the proton beam during propagation through a low density vapour. The proton beams, generated at a repetition rate of 5 Hz using only 190 mJ of laser energy, exhibit a hundred-fold increase in flux compared to beams from a solid target. Coupled with the higNature communicationsStable laser-acceleration of high-flux proton beams with plasma collimation.PMC11759682EP/Y001737/1Hyland CGray RJDover NPHicks GSThomas AGRGauthier MStreeter MJVDiIorio STreffert FAhmed HIstokskaia VKing MGlenn GDAstbury SDann SJDGiuffrida LCurry CBMcKenna PParsons PPalmer CAJBorghesi MXu NGlenzer SHSymes DRNajmudin ZSpindloe CGreen JSParisuana CEttlinger OCMargarone DDzelzainis TMcCusker OBourgeois NLoughran BfalseStable laser-acceleration of high-flux proton beams with plasma collimation.Laser-plasma acceleration of protons offers a compact, ultra-fast alternative to conventional acceleration techniques, and is being widely pursued for potential applications in medicine, industry and fundamental science. Creating a stable, collimated beam of protons at high repetition rates presents a key challenge. Here, we demonstrate the generation of multi-MeV proton beams from a fast-replenishing ambient-temperature liquid sheet. The beam has an unprecedentedly low divergence of 1° (≤20 mrad), resulting from magnetic self-guiding of the proton beam during propagation through a low density vapour. The proton beams, generated at a repetition rate of 5 Hz using only 190 mJ of laser energy, exhibit a hundred-fold increase in flux compared to beams from a solid target. Coupled with the hig2025-01-01T00:00:00Z2025 Jan2025-04-05T00:26:10.368Z2025-04-05T00:26:10.368ZS-EPMC117596823985607010.1038/s41467-025-56248-4