Laser Megajoule target and spider. The Laser Megajoule (LMJ) is an experimental nuclear fusion device being built near Bordeaux, France, using the inertial confinement fusion (ICF) method. It uses 240 laser beams and 1.8 megajoules of power to heat a target (hohlraum, here a gold-plated cylinder) to the point where it emits X-rays. The X-rays heat the deuterium-tritium fuel pellet (sphere) until fusion and power generation occurs. The fuel pellet, less than a millimetre across, is held in place in the hohlraum by spider threads. Construction of the LMJ started with the Laser Integration Line (LIL, 8 lasers), completed in 2002 and due to be expanded into the full LMJ by 2012. Photographed at the Valduc facility of the French Atomic Agency (CEA).