Stellarator symmetry

Stellarator symmetry is a property of typical stellarator magnetic configurations. In a cylindrical coordinate system, it is expressed as follows for a scalar field:

$\psi (R,\phi ,Z)=\psi (R,-\phi ,-Z)\,$

with respect to the symmetry plane φ = 0. Likewise, for a vector field:

$\left(B_{R},B_{\phi },B_{Z}\right)_{(R,\phi ,Z)}=\left(-B_{R},B_{\phi },B_{Z}\right)_{(R,-\phi ,-Z)}$

With N-fold rotation symmetry around the Z axis, there are 2N such planes.