Kruskal-Shafranov limit

The Kruskal-Shafranov limit is a critical concept in plasma physics related to magnetic confinement for fusion reactors. It defines a threshold for the electric current within a plasma. If this current exceeds the Kruskal-Shafranov limit, a violent instability known as a series of kinks can occur, leading to significant plasma loss and energy leakage.1

Achieving stable plasma confinement is essential for controlled nuclear fusion. This involves creating magnetic field configurations that balance the outward pressure of the plasma with inward magnetic forces, ensuring the plasma remains in a stable equilibrium. While classical diffusion is expected, experimental plasmas often lose energy much faster due to anomalous transport, a phenomenon linked to plasma turbulence. The Kruskal-Shafranov limit is particularly relevant in toroidal (doughnut-shaped) confinement systems, where maintaining plasma stability is paramount for achieving fusion conditions.21