Laser fusion breakthrough brings greater energy explosion

Recently, scientists from the National Ignition Facility at Lawrence Livermore National Laboratory in California produced a burst of energy by bombarding hydrogen pellets with 192 laser beams, briefly reproducing the fusion process that powers the sun. This is a repeat of an experiment in December last year, but this time the scientists generated more energy, with a gain almost double that of the incident laser.

We will repeat the ignition again, "Richard Towne, deputy director of the Livermore laser fusion project, said in an interview. On Monday, he gave a speech at a conference in Denver on the July experiment.

Livermore's research results have raised hopes that one day, nuclear fusion can be used to generate a large amount of electricity without producing greenhouse gases or long-lived radioactive waste.

The experiment in December last year generated approximately 3 megajoules of energy, equivalent to approximately 1.5 pounds of TNT, or 1.5 times the energy of the incident laser, earning a whirlwind of praise. This is the first time a fusion reaction has occurred in a laboratory environment where the energy generated exceeds the energy required to initiate the reaction. The experiment in July is basically the same as the experiment in December. We expect a similar output, "Dr. Tang said. Approximately three megajoules. The actual output is 3.88 megajoules. Better than predicted results indicate that laser fusion can become more efficient with some adjustments. But small changes can also lead to fusion failure.

Dr. Town said that the fusion experiment conducted in June a month ago was also expected to generate about 3 megajoules of heat, but in reality only 1.6 to 1.7 megajoules of heat were generated. The most recent attempt this month, as part of efforts to maintain nuclear weapons without conducting underground nuclear tests, generated slightly more than two megajoules of energy, in balance with laser energy balance. It's a bit surprising that we didn't ignite all of these substances, "Dr. Tang said.

By analyzing the results, Livermore scientists now believe they have a better understanding of what is happening. Firstly, 192 lasers are not perfect. Every time a laser is emitted, there are some changes, "Dr. Tang said. The laser energy did not reach a perfect balance to compress the hydrogen fuel capsule, but a slight imbalance would push the capsule in one direction. Some energy has been lost, and an inward implosion will not heat the hydrogen too much. There are also subtle changes in the fuel tanks that affect fusion reactions. Computer simulations now indicate that the range of output energy may be large. It may drop to 1.4 megajoules, "Dr. Town said. If the stars are aligned and everything is normal, it may reach seven megajoules.

Siegfried Glenzer, a scientist at the SLAC National Accelerator Laboratory in Menlo Park, California, led preliminary fusion experiments at the Livermore facility a few years ago, In fact, the gain of the last launch has increased, which is encouraging news, indicating that the current implosion has not been fully optimized. "He said of the progress in July. The national ignition device is about to begin a series of new experiments, with the aim of producing higher fusion production more consistently. The energy of the laser in this facility has been upgraded from 2.05 megajoules to 2.2 megajoules. The latest progress occurred after the last upgrade from 1.9 megajoules. The additional energy is expected to bring about further improvements. If you can effectively couple more energy to hotspots, you should achieve more production, "Dr. Tang said. You can do this with a larger hammer.

Source: Laser Network