Our ever-growing need for clean sources of energy has pushed fusion research to the point where we know largely understand the way in which plasma acts inside a fusion reactor. However, there is still much to figure out in terms of plasma physics.
Scientists are currently developing a new type of reactor called a tokamak. This device produces energy with the help of superheated plasma. However, this concept has proved the fact that there are still several physical phenomena which we do not fully understand.
One of them is turbulence. While it is accepted that plasma turbulence in a tokamak reactor is essential to determine its level of containment and performance, we do not know how to predict it, or what exactly are the factors that can affect it.
Our lack of knowledge is partially due to the complex mechanics of a fusion reactor. The core concept is that energy is produced by fusing two hydrogen atoms heated to over 100 million degrees Celsius (in order to become plasma), which form a new element but also release a free neutron. Tokamak reactors also use extremely strong magnetic fields in order to contain the plasma, due to the fact that it would melt anything it would touch.
Now, between the high temperatures and the magnetic containment, scientists have discovered that turbulences appear in the plasma. These can affect the reactor’s ability to produce sustainable energy.
Luckily, our technology again saves the day. The massive processing power offered by supercomputers have enabled us to more accurately predict plasma behavior, through the use of simulations.
Physicists from the University of California, ran a series of simulations at Lawrence Berkeley National Laboratory’s National Energy Research Scientific Computing Center, in order to determine if the energy transported by the electrons in plasma can be predicted, and whether it is multiscale in nature or not.
The tests used approx. 70 million hours of computing time and have replicated the conditions measured in a plasma run at the DIII-D tokamak at General Atomics. The results have shown scientists that electron energy transport does, in fact, have a multiscale character. This essentially means that the behavior of the electrons can also be predicted at much larger scales than in the experiment.
These simulations have helped specialists better understand what happens in a tokamak reactor when it is fired up. Furthermore, they have shown that the same type of simulation can be used by researchers in order to better understand the physics of plasma in fusion reactors and to design more efficient future devices of this nature.
Tokamak reactors are still in their infancy, in terms of development, however, many consider them to be the best alternative to the extremely harmful reactors that are currently in use. There is a high possibility that current research projects will produce a practical tokamak design which we will be able to build in the next 20-30 years.