LLNL, Livermore, California, USA
The National Ignition Facility (NIF) is the world’s most energetic laser capable of delivering 2.05MJ of energy with peak powers up to 500 terawatts on targets a few mms in diameter. This enables extreme conditions in temperature and pressure allowing a wide variety of exploratory experiments from triggering fusion ignition to emulating temperatures at the center of stars or pressures at the center of giant planets. The capability enabled the groundbreaking results of December 5th, 2022 when scientific breakeven in fusion was demonstrated with a target gain of 1.5. A key aspect of supporting various experiments at NIF is the ability to custom shape the pulses of the 48 quads independently with high fidelity as needed by the experimentalists. For more than 15 years, the Master Oscillator Room’s (MOR) pulse shaping system has served NIF well. However, a pulse shaping system that would provide higher shot-to-shot stability, better power balance and accuracy across the 192 beams is required for future NIF experiments including ignition. The pulse shapes requested vary drastically at NIF which led to challenging requirements for the hardware, timing and closed loop shaping systems. In the past two years, a High-Fidelity Pulse Shaping System was designed, and a proof-of-concept system was shown to meet all requirements. This talk will discuss design challenges, solutions and how modernization of the pulse shaping hardware helped simple control algorithms meet the stringent requirements set by the experimentalists.
LLNL Release Number: LLNL-ABS-848060
