13 Dec 2005
Scientists validate key models predicting plasma flow and ignition temperature.
The National Ignition Facility (NIF), US, has received a major boost on its quest to achieve inertial confinement fusion according to research published in Physical Review Letters (95 215004). Scientists fired-up four laser beams to show that NIF's millimetre-sized hohlraum target can generate slow developing plasma with controlled symmetry necessary for ignition.
"This is a very clear demonstration that NIF is indeed on the path toward ignition," said NIF physicist Eduard Dewald. "The data we were able to acquire proved in real terms that the computer projections are remarkably accurate [and that] NIF is capable of producing high-quality laser beams."
Ultimately, a total of 192 laser beams will be used to heat the interior of the gold plated hohlraum and create X-rays that ablate a deuterium-tritium fuel capsule placed inside the cylindrical target. NIF will be used to study high energy phenomena under confined experimental conditions and forms an integral part of the US government's nuclear stewardship program.
In the latest research, the team from US-based Lawrence Livermore National Laboratory, Los Alamos National Laboratory, General Atomics and the UK's Atomic Weapons Establishment irradiated each hohlraum with 2 ns laser pulses of ultraviolet radiation (5 - 13 kJ). The measured x-ray flux around the target showed filling signatures that coincide with hard x-ray emission from plasma streaming out of the hohlraum.
NIF, which is now more than 80% complete, is currently scheduled to be fully operational in mid-2009.
Author
James Tyrrell is reporter on Optics.org and Opto & Laser Europe magazine.
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