Pinch (plasma phys
Pinch (plasma physics)
A pinch is the compression of an electrically conducting filament by magnetic forces.
The conductor is usually a plasma, but could also be a solid or liquid metal. In a Z-pinch, the current is axial (in the z direction in a cylindrical coordinate system) and the magnetic field is azimuthal; in a theta-pinch, the current is azimuthal (in the theta direction in cylindrical coordinates) and the magnetic field is axial. The phenomenon may also be referred to as a "Bennett pinch"[1] (after Willard Harrison Bennett), "electromagnetic pinch",[2] "magnetic pinch",[3] "pinch effect"[4] or "plasma pinch".[5]
Pinches occur naturally in electrical discharges such as lightning bolts,[6] the aurora,[7] current sheets,[8] and solar flares.[9] They are also produced in the laboratory, primarily for research into fusion power.
