Electra: a KrF electron-beam-pumped high-average-power laser system for inertial confinement fusion applications

Electra is an electron beam pumped laser being developed at the Naval Research Laboratory as an inertial confinement fusion (ICF) driver. Two opposing 500 kV, 100 kA electron beams pump the main amplifier, which achieves energies of 730 J over a 100 ns pulse at 248 nm when run in an oscillator configuration. KrF lasers have been shown to have intrinsic efficiencies of greater than 12% and, based on that, wall plug efficiencies of >7% are projected for an IFE system based on our established improvements in laser physics and pulsed power technologies. The Electra main amp has run at rep-rates of 1 Hz, 2.5 Hz, and 5 Hz in runs exceeding 10,000 shots. This paper will present an overview of the Electra accomplishments and highlight recent research, including integrating Electra's amplifiers into a durable full laser system, interferometric measurements of the near field spatial distortions in the amplifiers and their effect on the far field profile, and spatially and temporally resolved temperature measurements of the electron beam transmission foil.