The energy generated by nuclear fusion holds considerable potential as a clean and almost limitless source of power, but many obstacles need to be overcome before practical reality can be reached – and scientists may have just climbed on to each other.
New models of unwanted fusion phenomena called ‘chirping’ where significant heat can be lost from the reaction process have given experts a better idea of how this happens and how to prevent it from happening.
As construction work continues on future fusion reactors, it is good knowledge to be in the public domain.
This conclusion applies to a typical donut-shaped fusion reactor design called a tokamak, such as being made in Iter, southern France. These reactors rely on a delicate balance between external magnetic fields and the dynamic plasma’s own writing magnetism to keep the entire fusion process flowing.
“For the fusion device to work, you need to make sure that the highly energetic particles within it are very well confined within the plasma core,” says physicist Vinicius Duttart of the Princeton Plasma Physics Laboratory (PPPL). “
“If those particles move to the edge of the plasma, you cannot maintain the steady-state burning plasma needed to make fusion-powered electricity a reality.”
Chirping occurs when there is a change in the frequencies of high-energy plasma waves, saving energy and heat, and possibly damaging the edges of the tokamak. Thanks to highly detailed, three-dimensional computer simulations created by researchers, some of the mechanisms behind that behavior have been identified.
The models showed fast moving particles in the plasma core hitting the waves flowing through the ionized gas. When this happens, flakes are formed that move towards the edge of the plasma current.
Reassuringly, the models coincide with previous simulations, although new research adds additional depth and detail to what is actually going on inside the reactor. The final effect is to reduce the efficiency of the tokamak, which is not something you really want when you are trying to get a next-gen power source up and running.
“If you understand this, you can find ways to operate fusion facilities without it,” says physicist Rozko White.
What scientists are trying to do with Tokamak and other nuclear fusion designs is to mimic the reactions on the Sun – the small challenge. If we get it right, this process of mixing two atomic nuclei into one can give us a way to generate electricity from simple things like water and salt with very little waste products.
While the idea is a great one, it is intended to work in a way that is reliable, inexpensive, and accessible to all, still in some way closed. However, there are expectations that Fusion Energy may contribute to the grid within the next 10 years.
The simulation and software processing tools developed by the researchers here were custom-made for the job – such as in White’s words “building a microscope” to capture a specific event – and using the same model to re-analyze and improve in the future Can be done for. Tokamac Design.
“The devices developed in this research have enabled a glimpse into the complex, self-organized dynamics of lamps in a tokamak,” says Duttart.
Has been published in Physics of plasmas.