A kink instability (also kink oscillation or kink mode), is a
current-driven
plasma instability characterized by transverse displacements of a plasma column's cross-section from its
center of mass without any change in the characteristics of the plasma. It typically develops in a thin
plasma column carrying a strong axial current which exceeds the
Kruskal–Shafranov limit and is sometimes known as the Kruskal–Shafranov (kink) instability.
The kink instability was first widely explored in
fusion power machines with
Z-pinch configurations in the 1950s.
It is one of the common
magnetohydrodynamic instability modes which can develop in a pinch plasma and is sometimes referred to as the
mode.
(The other is the
mode known as the
sausage instability.)
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.
Plasma Dictionary
As it develops at fixed areas in the plasma, kinks belong to the class of "absolute plasma instabilities", as opposed to convective processes.
References
Plasma instabilities
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