Physics: Burning issues in nuclear fusion

 
This week, a paper reporting that the self-heating of matter in the plasma state was achieved by nuclear fusionNature Will be published in.This finding is an epoch-making achievement toward the possibility that fusion energy will be a feasible energy source.at the same timeNature physics The paper published in is described in the design of experiments optimization that made this result possible.

Nuclear fusion, which fuses atomic nuclei and releases energy, has the potential to be a sustainable energy source.Fusion is a physical process that supplies energy to the stars in the universe, but it is difficult to reproduce in the laboratory and consumes much more energy than it emits.Combustion plasma is an important step toward the realization of nuclear fusion, which is thought to generate surplus energy.In combustion plasma, fusion is the primary heat source and the temperature of the fuel in the plasma state is maintained high enough to trigger the continuous occurrence of fusion reactions.In this paper by Alex Zylstra et al., It is reported that combustion plasma was realized in the inertial confinement fusion experiment.In this experiment, the fusion reaction is initiated by compressing and heating a capsule filled with thermonuclear fuel.

In an experiment conducted at the US National Ignition Facility, 192 laser beams were used to rapidly heat and implosion a capsule filled with 200 micrograms of deuterium-tritium fuel to achieve plasma combustion. Sufficient temperature and pressure were reached to trigger the heated fusion reaction.Research on the realization of plasma combustion has been carried out so far, but due to the problem of controlling the shape of the plasma so that the process of storing energy in the plasma by the laser beam is not disturbed, the result is as expected. Did not go up.Now, Zylstra and colleagues have improved the design of the experiment to allow capsules that can absorb more energy while retaining more fuel in the plasma state than ever before.The performance achieved by these experiments (energy yields up to 170 kilojoules) was three times the energy yields obtained in previous experiments.

 
* This article is reprinted from "Nature Japan Featured Highlights".
Reprinted from: "Physics: An Urgent Problem for Fusion Reactors'