Physical parameters at ignition for ‘I’ model (red) and ‘H’ model (blue) for aspect ratio = 3 (solid) and 7 (dashed) plasma versus elongation κ. For ‘H’ model, h = 0.2 (see Eq. (12)) is used. Panel (a) shows marginal toroidal field B_T in unit T, panel (b) exhibits toroidal current I_P in MA, panel (c) refers to average density n ¯ in 10²⁰/m³ and panel (d) indicates volume averaged β values. The black curves represent Tryon limits.