TJ-II:Magnetic field

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The complexity of the TJ-II magnetic field is patent from the following examples, in which a magnetic field property is mapped onto the last closed flux surface (configuration 100_44_64). The influence of the toroidal field coils is clearly visible (there are 32 toroidal field coils, leading to the striped pattern), as well as that of the circular/helical coils (continuous red stripe in the toroidal direction in the first two figures below).

TJ-II: Abs(B)

Absolute value of the magnetic field, |B| (T).

TJ-II: Curvature κN

Normal magnetic curvature of the magnetic field, κN. Positive values of κN are regions where curvature-driven modes are expected to be stable (note that this figure corresponds to the vacuum magnetic field -without plasma- so that strictly speaking it is not correct to speak about plasma stability).

TJ-II: Local shear, slocal

Local shear of the magnetic field. TJ-II is a low-shear device, meaning the global shear is small; however, the value of the local shear can be quite large.

See also