Britannica Sources used in this answer

What causes the pinch effect in a cylindrical plasma?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

How scientists use lasers to learn about the universe — plasma Learn about the PHELIX (Petawatt High-Energy Laser for Heavy Ion Experiments) laser at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. PHELIX is used for plasma and atomic physics research.

The pinch effect in a cylindrical plasma is caused by the interaction between an electric current and the resulting magnetic field. When an electric current is applied so that it flows parallel to the axis of a cylindrical plasma, it generates a magnetic field that exerts inward-directed magnetic forces on the current-carrying particles.12

These forces cause the plasma to constrict, or "pinch," effectively compressing and heating the material. While this process can confine the plasma, the configuration is inherently unstable; the plasma cylinder tends to develop kinks or break into segments, often described as resembling a string of sausages. Consequently, achieving stable confinement for applications like nuclear fusion requires augmenting this effect with more complex magnetic-field configurations to prevent the plasma from rapidly escaping its equilibrium state.123