IOP Groups
Lasers
Plasma physics research into the behaviour of matter under extreme ('High Energy Density') conditions is carried out at several large laser facilities worldwide. Typical temperatures are in the range (10k to 0.1G)K, with densities from (0.1 to 10M) kg/m3, inducing pressures of (0.1G to 100T) Pa. Access to these conditions is provided by laser facilities operating on nanosecond (10-9 s) timescales with powers of 1TW to 1PW, using targets with scalelengths of 10-6 to 10-3 m in suitably designed vacuum interaction chambers such as the HELEN laser at AWE, shown here.
Other examples include and VULCAN at RAL, OMEGA at the University of Rochester laboratory for laser energetics and NIF which is under construction at Lawrence Livermore National Laboratory in California. One of the principal applications of these laser technologies is to Inertial Confinement Fusion (ICF), with the "fast ignition" concept being of particular interest at the current time. The goal of ICF is to use a set of laser beams to compress and heat a pellet of DT to ignition. In fast ignition the compression is carried out by relatively long pulse lasers and the resulting high density DT fuel is then subjected to a multi-petaWatt ignitor beam. Problems involved with guiding the ignitor beam through the coronal plasma to the compressed fuel have been overcome at RAL by the use of a gold cone which keeps the channel clear, although the implosion hydrodynamics become more complex (non-spherical). In the UK, AWE is embarking on a new national laser facility (Project ORION) in collaboration with the Rutherford-Appleton-Laboratory. This will provide a unique capability for High Energy Density plasma physics research into the next decade, coupling nanosecond and picosecond laser technology from the two laboratories.
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