Scientists have discovered a new plasma confinement state that could bring us a step closer to achieving fusion energy.
Research on high-density and high-temperature plasma confinement by magnetic fields is being conducted across the globe in hopes of achieving the feat successfully, and these findings provide valuable new insight, the National Institutes of Natural Science reported.
As the core temperature of magnetically confined plasma rises, the flow of disturbed plasma known as turbulence appears and moves circumferentially like a "surge of waves." These plasmas contain confinement areas known as magnetic islands in which there is no temperature gradient, leading to turbulence. If turbulence is generated outside of the magnetic islands, where a temperature gradient is present, it moves into the islands. The intensity of the turbulence determines the confinement state inside the magnetic island. The success of future fusion plasma will depend largely on the improvement of the magnetic island's confinement state.
Scientists have discovered for the first time a new confinement state inside a magnetic island. The finding will help improve the confinement of the fusion reactor plasma, potentially opening the door for future fusion energy research. The discoveries included a "particularly superlative magnetic island" and self-regulated oscillations between two different adiabaticity states. High adiabaticity means good confinement performance in the magnetic island. The oscillations occurred between a the "good state" of adiabaticity, which is five times greater than outside, and the "even more superlative state" in which adiabaticity was 40 times greater than outside. The team observed a never-before-seen state where temperature variations were transferred in the magnetic island and another that included small temperature variations with repeatedly alternating cycles.
"This discovery of the self-regulated oscillation means that there is variety in the performance of plasma confinement (adiabaticity). This discovery provides new guiding principles for producing a magnetic island with good confinement condition, and will greatly contribute to fusion research. Further, this newly discovered mechanism may also be significant for interpreting space and solar physics effects, and we anticipate the wide circulation of these results academic research," the researchers stated.
The findings were published in a recent edition of the journal Scientific Reports.