Monoenergetic electron beam generation from a high-density plasma produced by a 2-TW, 50-fs laser pulse

Abstract

Generation of a monoenergetic electron beam with an energy of up to 23 MeV has been demonstrated in laser‐driven plasma acceleration. A monoenergetic electron beam with an energy of 7 MeV was obtained only in the narrow electron density range around 1.5 × 1020 cm−3, when a nitrogen gas jet was irradiated by a 2‐TW, 50‐fs laser pulse. On the other hand, a monoenergetic electron beam with an energy of 23 MeV was obtained only in the narrow electron density range around 4 × 1019 cm−3, when a helium gas jet was irradiated by a 3‐TW, 50‐fs laser pulse. Plasma diagnostics based on the optical measurements were conducted simultaneously with the electron beam measurement. According to the plasma diagnostics, the mechanism of the monoenergetic beam generation is also discussed.