Axisymmetric toroidal magnetic configurations relevant to current andfuture tokamak experiments are analytically modelled taking into account anarbitrary aspect ratio, noncircularity and up-down asymmetry of fluxsurface shapes. It is shown that equilibrium tokamak magnetic fields can besatisfactorily described using only four geometric parameters, whichdetermine the shape and position of the flux surfaces. These are theShafranov shift, the elongation, and the parameters of triangularity and ofup-down asymmetry. To cover the variety of observed flux surface shapes,three different analytical expansions are provided. Comparison of themodelled with the equilibrium flux surfaces in NSTX (Princeton), JET(Abingdon) and TCV (Lausanne) demonstrates good coincidence.
Extension of neoclassical rotation theory for tokamaks to realistically account for the geometry of magnetic flux surfaces