H-Mode Discharges

In H-mode discharges, the improved edge confinement leads to a large edge current density driven by the strong pressure gradient built up in that region. In the reconstruction, it is essential to allow the plasma edge current density to be finite in this type of discharge. Forcing the edge current density to vanish often leads to an incorrect plama boundary incompatible with the plsama edge as expected from the Thomson scattering data. The JT SNAP file allows the edge current density to be finite yet remain small by constraining it to vanish only weakly