View source for TJ-II:Magnetic field

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|flux surface]] (configuration 100_44_64). The influence of the [[TJ-II:Coil system|toroidal field coils]] is clearly visible (there are 32 toroidal field coils, leading to the striped pattern), as well as that of the [[TJ-II:Coil system|circular/helical coils]] (continuous red stripe in the toroidal direction in the first two figures below).

[[File:TJ-II AbsB.jpg|800px|thumb|center|TJ-II: Abs(B)]]
Absolute value of the magnetic field, |B| (T).

[[File:TJ-II Curvature.jpg|800px|thumb|center|TJ-II: Curvature &kappa;<sub>N</sub>]]
Normal [[Magnetic curvature|magnetic curvature]] of the magnetic field, &kappa;<sub>N</sub>. 
Positive values of &kappa;<sub>N</sub> 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).

[[File:TJ-II Local shear.jpg|800px|thumb|center|TJ-II: Local shear, ''s''<sub>local</sub>]]
[[Magnetic shear|Local shear]] of the magnetic field. TJ-II is a low-shear device, meaning the [[Magnetic shear|global shear]] is small; however, the value of the local shear can be quite large.

== See also ==
* [[TJ-II:Magnetic coordinates]]