Z-pinch is a confinement concept that squeezes a 📝plasma with the magnetic field of a current driven through it: the current runs along the column's axis — the z axis of cylindrical coordinates, hence the name — and the azimuthal field it generates pinches the column inward.
The pinch is the oldest idea in controlled 📝fusion. Willard Bennett worked out the equilibrium of a current-carrying plasma column in 1934, and pinch machines dominated the field's first decade — most famously Britain's ZETA, whose claimed fusion neutrons in 1958 turned out to be instability artifacts. The instabilities were the point of failure generally: a simple Z-pinch column kinks like a garden hose and necks off in sausage-shaped bulges within microseconds, and that fragility is what drove the field toward the 📝Tokamak, which can be read as a pinch tamed by bending it into a torus and adding a strong stabilizing 📝toroidal field.
The concept has two modern lives. Sheared-flow stabilization — flowing the plasma faster at the column's edge than at its core — suppresses the classic instabilities without any external magnets, the approach Zap Energy is scaling from the university FuZE experiments. And at Sandia National Laboratories' Z machine, the world's most powerful pulsed-power facility, pinch-driven implosions compress fuel directly in the MagLIF concept, a branch of 📝magnetized target fusion.