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ITB Control with LH Heating & Current Drive. LH should be very effective in controlling density peaking Current drive phasing can either increase or decrease V loop Increase V loop with LHCD Increase Ware Pinch Trigger ITB at will Expand ITB foot location Reduce V loop with LHCD
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ITB Control with LH Heating & Current Drive LH should be very effective in controlling density peaking Current drive phasing can either increase or decrease Vloop Increase Vloop with LHCD Increase Ware Pinch Trigger ITB at will Expand ITB foot location Reduce Vloop with LHCD Reduce Ware pinch, prove ITB due to Ware pinch Control density peaking: Ohmically heated ITB (hi B, low Ip) ITB with off-axis ICRH in H-mode, use LH instead of on-axis ICRH Also, following H to L transition LH heating of electrons should drive Trapped Electron Modes, as in previous on-axis cases, limiting density gradient [IAEA 2006, etc] Document fluctuations and simulate with GS2/GYRO using synthetic PCI Balance accessibility (higher n||) against efficiency (~ n||-2) Have done well with n||=1.6; expect 25% of this efficiency at n||=3.2 n|| upshifts after launch, helping some Lower density and higher field better Cryopump and 7.5 – 8 Tesla desirable Only need to access foot of ITB 2000 H-Mode Off-axis ICRH Ohmic H-Mode 0.8 MA Fig. 2-5: J. Liptac, PhD Thesis, MIT (2006). 2007 C-Mod Ideas Forum