Stability analysis of the high poloidal bet scenario on DIII-Dtowards operation athigher plasma current

The high poloidal beta scenario with plasma current I$^{\mathrm{P}}$\textasciitilde 600 kA and large-radius internal transport barrier (ITB) on DIII-D is subject to n$=$1 MHD kink modes when the current profile becomes very broad at internal inductance values li\textasciitilde 0.5-0.6. It is desirable to extend this scenario to higer plasma current (\textasciitilde 1 MA) for highernormalized fusionperformance. However, higher current at constant normalized beta, ?$^{\mathrm{N}}$\textasciitilde 3, would reducethe poloidal bet, ?$^{\mathrm{P}}$, below the threshold for ITB sustainment, observed at ?$^{\mathrm{P}}$\textasciitilde 1.9. Thus, to avoid loss ofthe IT,?$^{\mathrm{N??}}$ must be increased together with I$^{\mathrm{P}}$ while avoiding the kink instability. MHD analysis is presented that explains possible paths to high?$^{\mathrm{N}}$stability limit for the kink mode in tis scenario. *Work supported by National Magnetic Confinement Fusion Program of Chin under 2015GB110001 and 2015GB102000£¬National Natural Science Foundation of China under Grant No. 1147521 and by US DOE under DE-FC02-04ER54698.