Scientists Discover How to Keep Plasma In Fusion Reactors Stable

Researchers made an enormous leap recently by moving one step closer to stable fusion nuclear energy. They discovered a way to stabilize plasma in fusion reactors, thus preventing temperatures and densities from oscillating.

It is believed that nuclear fusion is the answer to providing inexhaustible green energy just as long as researchers can control this kind of power source. And now, it seems that they are closer to stabilizing plasma in fusion reactors, even though it is through simulations!

Recently, a group of researchers in New Jersey at the US Department of Energy’s Princeton Plasma Physics Laboratory from the Princeton University ran several simulations, trying to stabilize plasma in fusion reactors. Lo and behold, they discovered a way to do it!

It is a known fact that plasma is one of the states of matter. If we talk about our typical situations on earth, plasma cannot exist as a liquid, solid or gas matter. On the contrary, it is found naturally in stars in large amounts.

On Earth, scientists are able to generate plasma or this exceedingly hot matter state that is formed in fusion reactors by highly charged particles. That said, it is quite a challenging process to stabilize the plasma.

More often than not, plasma is found oscillating in density and temperatures, and due to this, there is generally a halt in the nuclear fusion reaction – a process called sawtooth instability which occurs when the current becomes strong enough to destabilize and halt the reactions.

However, the scientists in New Jersey might just have found a way to stabilize plasma through simulation in nuclear fusion reactors. Researchers followed the examples set by the stars in the universe and tried to replicate those same processes within several fusion reactors.

In the reactors, super-heated hydrogen atoms suspended in plasma, crash into each other, which result in splitting of atoms into highly charged ions and electrons. The ions and electrons then fuse to form helium.

This process generates high amounts of heat and energy that can be harnessed for the production of electricity.

To keep the current in the core of the plasma, the reactor makes use of magnetic flux pumping mechanism. This also keeps some of the plasmas stable to keep the reactions going rather than halting it.

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If we go by the latest simulations, two hybrid scenarios can prompt magnetic flux pumping. One scenario is where the plasma is stable (H-mode) while the other scenario is in which the plasma leaks some kind of energy (L-mode).

In the PPPL simulations, the flux pumping was developed with a hybrid scenario where the current remains flat in the plasma core and the pressure of the plasma is sufficiently high. The combination results in a ‘quasi-interchange mode’ that mixes up the plasma while deforming the magnetic field.

This mixing effect ensures that the current maintains flatness while avoiding the possibility of sawtooth instability formation.

This research was led by Isabel Krebs, post-doctoral research associate, who talked about the future applications of this discovery saying, "This mechanism may be of considerable interest for future large-scale fusion experiments such as ITER.”

Clearly, this breakthrough in the stabilizing of plasma is a step in the right direction towards going green in the future.

Details of this new research have been published in the Physics of Plasma journal.