The reference shot will be the recent high betaP shot #201927 (all co-beams) but with a stable and low ne (~7.5*1019m-3) with ITB and low betaN (3.5) during the flat-top. The counter-Ip NBI and modulated O-mode ECH are used to scan the torque and electron temperature, respectively. This is possible because the maximum NBI power from counter 210s is about 4 MW. There is room to reduce the input NBI torque while maintaining high NBI power. And the high confinement and ITB in βP scenario are not mainly determined by the large rotation. The O-mode ECH can also penetrate into the core region of high density (ne>6*1019m-3) with optimal parameters (In addition, based on the recent developed hybrid scenario shot #200199, the low rotation (Vt0<80km/s, Mach<0.15) and high Te (Te0~Ti0~4.5keV) can be achieved in high density (ne>7.5*1019m-3) regime with counter-NBI and near on-axis (rho~0.3) O-mode ECH). Both the transport of intrinsic and external injection impurities (W or Xe, Ar, Helium) will be studied. If the experiment goes smoothly, we will try to increase ne (~9*1019m-3 with ne ITB) and betaN (~4) to repeat the scan. 3.1 Torque scan Before 1.5s, the beams except 210s will be used (with gyrotrons if needed) to reproduce the reference shot, at this stage, no LBO is injected to keep the plasma stable. During 1.5-2.2s, 1MW counter 210 beam need to be injected to decrease the torque. After 2.2s, the counter NBI will be injected stepwise. It should be noted that firstly only one pulse LBO will be injected at t~4.1s so that the intrinsic and external injected impurities transport can be studied separately and LBO can be also replaced by IPD and gas puffing if needed. Then repeat above torque scan with multiple LBO injection. It should be noted that the impurity is injected since the ramp up phase because we want to try to consider the full and real process of impurity transport, f.g. the impurity transport from the wall to core during the Ip ramp up phase, and the real wall condition like KSTAR. If the impurity injection during the ramp up phase will kill the discharge frequently, only inject impurity during the flat top. 3.2 Torque+ECH scan Based on the torque scan, we put more on-axis O-mode ECH stepwise. 3.3 ECH scan with early counter beams and other impurities We want to establish a stable high betaP plasmas for long time, so the full NBI with co and counter-beams are used during the flat-top. Other impurities injection will also be tested.