Nuclear fusion instabilities detected with simulation code

The simulation code is able to calculate and predict changes in TAE instability to increase fast ion confinement and ensure the success of fusion reactions. 

The TAE instability occurs in the course of interactions between fast ions and the perturbed magnetic fields surrounding them. As a result, fast ions disengage from the plasma core, hindering ion trapping. 

In plasma particles, fast ions are much higher in kinetic energy than general ions and increase the temperature and performance of plasma necessary for nuclear fusion. Therefore, stable fast ion trapping is essential in maintaining a nuclear fusion reaction.

The team at the Korea Institute of Fusion Energy (KFE) was able to develop the code by using and improving upon the Gyro Kinetic Plasma Simulation Program (gKPSP) nuclear fusion simulation code, which was previously used for plasma transport analysis. The team added a feature to the code that allowed it to enable electromagnetic analysis, making the code capable of analysing TAE instabilities. 

“The newly developed code will be utilised in analysing the trapping of fast ions generated as a result of nuclear fusion reactions and heating of various types,” the institute explained, adding, “Plasma performance improvement is anticipated through optimal fast ion trapping."

The new code will be used for analysing the confinement performance of fast ions generated by different methods, including various heating devices and fusion reactions. 

Nuclear fusion joins together two atomic nuclei to create a single larger nucleus with slightly less overall mass, releasing extra energy. This is the reaction that keeps the sun and stars shining, controlled by gravity. However, while nuclear fission is easy to start and hard to stop, fusion has been, to date, impossible to sustain on Earth. This is due to multiple challenges, one of which is TAE instabilities. 

In 2020, the government declared its ambition for the UK to be the first country to commercialise fusion technology, with plans for a new prototype fusion energy plant – STEP (Spherical Tokamak for Energy Production) – to contribute to the grid by 2040. To support this goal, the UK government proposed to rule this type of energy through an “innovation-friendly” approach, different from that used for mature civil nuclear technology. 

China is also reportedly hoping to get an experimental nuclear fusion reactor running by 2040.

Currently, KFE is operating KSTAR (Korea Superconducting Tokamak Advanced Research), known as the "Korean artificial sun", which set the record in 2021 for the world’s longest plasma operation at ion temperatures of over one hundred million degrees for thirty seconds.

The KFE team's findings were published in the Physics of Plasmas.