Kink instability

One of the earliest photos of the kink instability in action - the 3 by 25 cm pyrex tube at Aldermaston.

A kink instability, also oscillation or mode, is a class of magnetohydrodynamic instabilities which sometimes develop in a thin plasma column carrying a strong axial current. If a "kink" begins to develop in a column the magnetic forces on the inside of the kink become larger than those on the outside, which leads to growth of the perturbation. As it develops at fixed areas in the plasma, kinks belong to the class of "absolute plasma instabilities", as opposed to convective processes. The kink instability was first widely explored in the Z-pinch fusion power machines in the 1950s.