Paths to Practical Laser Fusion Energy
Laser fusion involves the compression and heating of small targets using laser beams to reach conditions where the fuel, such as an initially frozen deuterium-tritium mixture, begins a fusion burn that releases large amounts of energy. If the fusion burn energy gain greatly exceeds the laser energy used to produce the fusion reactions, this can be an energy source for electrical power production. On this website the different approaches to achieving practical laser fusion energy will be presented and discussed. This website is supported by LaserFusionX Inc.
The Nation Ignition Facility (NIF) located at Lawrence Livermore National Laboratory is the world’s largest laser system. It consists of 192 beams utilizing flashlamp pumped Nd:glass amplifiers where the 1054 nm light is frequency multiplied to 351 nm prior to illuminating the targets. It’s primary operation utilizes indirect drive shown to the left. NIF has demonstrated fusion gains several times that of the laser energy, and capsule gains (fusion energy over x-ray energy delivered to target) of about 20. NIF is a “single shot” facility for research and lacks repetition rate and efficiency needed for energy production.
See: https://lasers.llnl.gov/science/achieving-fusion-ignition
With direct drive the laser beams directly illuminate the target enabling much higher efficiency than indirect drive.
It has been known for many years that shorter laser wavelength benefits both indirect and direct drive laser fusion. For both the onset of laser-plasma instabilities occur at higher intensity with use of shorter laser wavelength. In addition, for direct drive, shorter laser wavelength light produces higher ablation pressure and more efficiently implodes the pellet. The hydrocode simulations illustrate the effect on fusion gain for 351 nm, 248 nm and 193 nm light. https://royalsocietypublishing.org/rsta/article/378/2184/20200031/111735/Direct-drive-with-the-argon-fluoride-laser-as-a