In order to create a powerful energy source comparable to stars on the earth, scientists are working hard to study nuclear fusion technology, hoping to produce clean and unlimited energy. After the American scientific team successfully achieved “burning plasma” through high-power laser light earlier this year, they made new discoveries again. They discovered a strange and unexplainable ion behavior.
Since 2009, scientists at the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL ) have been working on nuclear fusion, firing 192 lasers to create enormous pressure and temperature. The ultraviolet energy of 1.9 megajoules (MJ) is irradiated into the hohlraum, which is as small as a ball bearing, and the fuel capsule in it is imploded, so that the atoms can be fused into helium and release huge energy.
In January this year, the nuclear fusion reaction of the National Ignition Facility successfully released 1.35 MJ joules of energy. This is the first time that the energy generated by the nuclear fusion process exceeds the total input energy. Although it is only a few nanoseconds, it is still nuclear fusion inertial fusion ( A new chapter in ICF).
Further analysis by the team found that the burning plasma presented in an unexpected way. The plasma showed higher energy than model predictions. For deuterium-tritium (DT) plasma in thermal equilibrium, the average neutron energy was higher than expected. . Alastair Moore, the lead author of the paper, said that there are things that we can’t predict with the normal radiation hydrodynamic code that simulates ICF, and probably can’t.
Scientists refer to the unexpectedly high-energy behavior of the plasma as the Doppler effect, like the change in the sound of a police siren when a police car or fire truck approaches and then moves away, Moore said. One explanation is Deuterium and tritium ions are not in balance, so more advanced simulation capabilities are needed for further research. We are working with teams from Los Alamos National Laboratory, Massachusetts Institute of Technology and Imperial College London, hoping to successfully solve the problem.
The team believes that the different behavior of ions in the fusion reaction than previously expected may provide important insights into the design of future laser fusion.
(First image source: LLNL)
