Fusion energy

Creating a star on Earth requires a delicate balance between pumping enormous amounts of energy into plasma to make it hot enough for fusion to occur and preventing that heat from escaping. Now, physicists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have identified a method by which instabilities can be tamed and heat can be prevented from leaking from the plasma, giving scientists a better grasp on how to optimize conditions for fusion in devices known as tokamaks.

An obstacle to generating fusion reactions inside facilities called tokamaks is that producing the current in plasma that helps create confining magnetic fields happens in pulses. Such pulses, generated by an electromagnet that runs down the center of the tokamak, would make the steady-state creation of fusion energy difficult to achieve. To address the problem, physicists have developed a technique known as transient coaxial helicity injection (CHI) to create a current that is not pulsed.

The swirls created by milk poured into coffee or the shudders that can jolt airplanes in flight are examples of turbulence, the chaotic movement of matter found throughout nature. Turbulence also occurs within tokamaks, doughnut-shaped facilities that house the plasma that fuels fusion reactions. Now, scientists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have discovered that turbulence may play an increased role in affecting the self-driven, or bootstrap, current in plasma that is necessary for tokamak fusion reactions.