Calculation of dipole and quadrupole fields in magnets with cylindrical and concentric exciting windings with linearly variable current density

Expressions are derived for determining dipole and quadrupole fields in magnets with cylindrical and concentric sector windings, with linearly variable current density. This kind of current density occurs, for example, in winding with thin and highly stranded superconducting cables. Numerical evaluation and comparison with constant-current-density windings, leads to equivalent magnetic field performance, if a constant cross-sectional current density in the conductor is assumed. (5 refs).