Prospects and progress at LIL and Megajoule

Abstract

The French Commissariat à l'Energie Atomique (CEA) began the construction of the Laser Megajoule (LMJ), a 240-beam laser facility, at the CEA Laboratory CESTA near Bordeaux. The LMJ will be a cornerstone of the CEA 'Programme Simulation', the French analog of the US Stockpile Stewardship Program.The LMJ is designed to deliver 2 MJ of 0.35 µm light to targets for high energy density physics experiments and to ultimately obtain ignition and propagating burn with DT targets in the laboratory.The Scientific conception and system design was completed in 1999 and was followed by the Demonstration of an Engineering Prototype which was achieved in early 2003 with the operation of one beam of the Ligne d'Intégration Laser (LIL) at CESTA, with 9.5 kJ of UV light (0.35 µm) in less than 9 ns from a single laser beam.The realization phase of the LMJ facility was initiated in March of 2003 with the start of construction of the building and the target chamber. This paper will present results from the commissioning phase of the LIL program in 2003 and 2004. The activation and commissioning of all eight beamlines of LIL over the next 2 years will be part of determining the final specifications and integration and commissioning plans for the LMJ, which is expected to demonstrate first light performance through 240 beams by 2009.

Design of a Rayleigh–Taylor experiment to measure strength at high pressures

“…Even within the constraints of using the ignition pulse as is, we believe such experiments are viable and informative without taxing the laser system. In addition to NIF 12,13,20 one may consider other systems such as the LMJ 33 as a possible platform. The laser pulse will probably vary from what we have used but we are confident that any quasi-isentropic ignition pulse can do doubleduty as a driver for material properties of solids.…”

Chromatism compensation of the PETAL multipetawatt high-energy laser

“…The PETAL facility is designed to deliver 3.6 kJ of energy in in 500 fs at the wavelength of 1.053 m and is an additional short pulse beam to the Laser Integration Line (LIL) 11 facility. The PETAL amplifier section has the same architecture as the LIL͞LMJ amplifier section 19 using a single 400 mm ϫ 400 mm beam.…”

“…For spatial filters, this effect ensures that only the central wavelength is collimated while the other wavelengths acquire a divergence or a convergence. For long-pulse laser systems such as NIF 10 or Laser Megajoule (LMJ) 11 , this effect can be neglected. But for short pulses, i.e., of large spectral bandwidth, this chromatic aberration can significantly distort temporally and spatially the beam in the focal plane.…”

Irradiation uniformity at the Laser MegaJoule facility in the context of the shock ignition scheme

“…The uncertainties concerning the laser-plasma interaction correlated to the shock ignition scheme have also motivated great interest in experimental activities [33][34][35][36][37][38][39] . Moreover, large laser facilities such as the National Ignition Facility (NIF) [40,41] in the USA and the Laser MegaJoule (LMJ) facility [42,43] in France as well as the smaller Orion facility [44] in the UK -all of them devoted to the indirect drive scheme -could be used to test relevant aspects inherent to the shock ignition scheme.…”