Comparisons among variations of marginal B_T required for all models at ignition relative to the ‘I’ model for an aspect ration A = 3 plasma, with edge parameter h (see Eqs. (10) and (12)). In order to accommodate all models in the same figure, we also used h to denote l ± 1 . (see Eq. (14)) for the ‘GB’ (broader) and ‘GP’ (more peaked) models. Panel (a) is the change of B_T in unit of T, and panel (b) is the change relative to that of the ‘I’ model (see Eq. (4)).