A fusion approach that uses the magnetic field from a large axial current to compress plasma radially — one of the simplest fusion geometries, now being pursued commercially by Zap Energy using sheared-flow stabilization.
A Z-pinch (or zeta pinch) passes a large electric current through a column of plasma. The current generates an azimuthal (circumferential) magnetic field that compresses the plasma radially toward the axis — the “pinch” effect. At sufficient current (megaamperes), the compression can reach fusion-relevant temperatures and densities.[1]
Classical Z-pinches are violently unstable to the m = 0 (sausage) and m = 1 (kink) MHD instabilities, which destroy confinement in microseconds. This limited early Z-pinch research (ZETA at Harwell, 1950s) and shifted attention to tokamaks.[2]
Sheared-flow stabilization: Zap Energy, a Seattle startup, uses axial sheared flows to stabilize the Z-pinch against sausage and kink modes. Their FuZE (Fusion Z-pinch Experiment) has demonstrated stable Z-pinch plasmas lasting hundreds of microseconds at fusion-relevant ion temperatures.[3]
Pulsed-power Z-pinch: Sandia National Laboratories’ Z Machine uses enormous pulsed currents (26 MA) to implode wire arrays and create intense X-ray sources. The magnetically driven ICF concept (MagLIF) adds laser preheating and axial magnetic field to a Z-pinch implosion.