Hi PER - Current Status

Current Status

In 2005 HiPER completed a preliminary study outlining possible approaches and arguments for its construction. The report received positive reviews from the EC in July 2007, and moved onto a preparatory design phase in early 2008 with detailed designs for construction beginning in 2011 or 2012.

In parallel, the HiPER project also proposes to build smaller laser systems with higher repetition rates. The high-powered flash lamps used to pump the laser amplifier glass causes it to deform, and it cannot be fired again until it cools off, which takes as long as a day. Additionally only a very small amount of the flash of white light generated by the tubes is of the right frequency to be absorbed by the Nd:glass and thus lead to amplification, in general only about 1 to 1.5% of the energy fed into the tubes ends up in the laser beam.

Key to avoiding these problems is replacing the flash lamps with more efficient pumps, typically based on laser diodes. These are far more efficient at generating light from electricity, and thus run much cooler. More importantly, the light they do generate is fairly monochromatic and can be tuned to frequencies that can be easily absorbed. This means that much less power needs to be used to produce any particular amount of laser light, further reducing the overall amount of heat being generated. The improvement in efficiency can be dramatic; existing experimental devices operate at about 10% overall efficiency, and it is believed "near term" devices will improve this as high as 20%.

HiPER proposes to build a demonstrator diode-pump system producing 10 kJ at 1 Hz or 1 kJ at 10 Hz depending on a design choice yet to be made. The best high-repetition lasers currently operating are much smaller; MERCURY at Livermore is about 70 J, HALNA in Japan at ~20 J, and LUCIA in France at ~100 J. HiPER's demonstrator would thus be between 10 and 500 times as powerful as any of these.

In order to make a practical commercial power generator, the high-gain of a device like HiPER would have to be combined with a high-repetition rate laser and a target chamber capable of extracting the power. Additional areas of research for post-HiPER devices include practical methods to carry the heat out of the target chamber for power production, protecting the device from the neutron flux generated by the fusion reactions, and the production of tritium from this flux in order to produce more fuel for the reactor.