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A kink instability (also kink oscillation or kink mode), is a 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.
A kink instability (also kink oscillation or kink mode), is a current
Currents, Current or The Current may refer to:
Science and technology
* Current (fluid), the flow of a liquid or a gas
** Air current, a flow of air
** Ocean current, a current in the ocean
*** Rip current, a kind of water current
** Current (stre ...
-driven plasma instability
The stability of a plasma is an important consideration in the study of plasma physics. When a system containing a plasma is at equilibrium, it is possible for certain parts of the plasma to be disturbed by small perturbative forces acting on it ...
characterized by transverse displacements of a plasma column's cross-section from its center of mass
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may ...
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
Fusion power is a proposed form of power generation that would generate electricity by using heat from nuclear fusion reactions. In a fusion process, two lighter atomic nuclei combine to form a heavier nucleus, while releasing energy. Devices de ...
machines with Z-pinch
In fusion power research, the Z-pinch (zeta pinch) is a type of plasma confinement system that uses an electric current in the plasma to generate a magnetic field that compresses it (see pinch). These systems were originally referred to simp ...
configurations in the 1950s. It is one of the common magnetohydrodynamic
Magnetohydrodynamics (MHD; also called magneto-fluid dynamics or hydromagnetics) is the study of the magnetic properties and behaviour of electrically conducting fluids. Examples of such magnetofluids include plasmas, liquid metals, ...
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
A sausage is a type of meat product usually made from ground meat—often pork, beef, or poultry—along with salt, spices and other flavourings. Other ingredients, such as grains or breadcrumbs may be included as fillers or extenders.
...
.)
If a "kink" begins to develop in a column the magnetic force
In physics (specifically in electromagnetism) the Lorentz force (or electromagnetic force) is the combination of electric and magnetic force on a point charge due to electromagnetic fields. A particle of charge moving with a velocity in an elect ...
s 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.
References
Plasma instabilities {{plasma-stub