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TC-9 Scaling of spontaneous rotation with no external momentum input NSTX to provide edge data (can we do an RF experiment on this?). Rotation with HHFW applied
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TC-9 Scaling of spontaneous rotation with no external momentum input NSTX to provide edge data (can we do an RF experiment on this?) Rotation with HHFW applied J. Hosea, R. E. Bell, B. P. LeBlanc, C. K. Phillips, G. Taylor,E. J. Valeo, J. R. Wilson (PPPL), P. M. Ryan, J. Wilgen (ORNL), et al. • Is there a drag on NB induced rotation with HHFW applied? • Is HHFW edge rotation consistent with heating and loss of energetic edge • ions? • Is HHFW induced rotation different between L and H modes? • do blobs and ELMs affect rotation? • Possible experiments: • Measure rotation at the end of a HHFW pulse with a 40 ms NB blip • end RF during NB blip at 40 ms, 30 ms, 20 ms, 10 ms, 0 ms • to determine drag from HHFW as a function of time • perform these measurements for L and H mode regimes
Edge toroidal velocity appears to be locked when the RF is on with the NB pulse 40 ms beam pulse – RF turned of at 30 ms during beam pulse The mechanism causing this effect is not understood but it may point to edge ion loss The RF apparently provides a drag on rotation inside the plasma as well
Revisiting possible parametric decay effects in plasma edge Poloidal heating in edge may eject energetic edge ions Edge ions are heated to hundreds of eV: CIII, CVI, LiII, and Helium Emission location for CIII and CVI is ~ 150 cm, just inside separatrix Edge ion heating may result in loss of energetic ions to SOL and the divertor
Strong interaction along field lines at lower phase/longer wavelength 130621 -90° 130608 -150° 130609 No RF PRF = 1.8 MW, PNB = 2 MW, IP = 1 MA, BT = 5.5 kG 0.33512 sec (-.25012) 0.33500 sec (-.25002) 0.34997 sec (-.24999) • “Hot region is much more pronounced at -90° than at -150° • Edge power loss is probably greater at -90° • Also, suggests fields move away from wall at -150° along with the onset density • Localized RF power in blob could affect edge electric field and edge rotation