Fast Ion Loss Detectors for Wave-Particle Interaction Studies - PowerPoint PPT Presentation

Fast Ion Loss Detectors for Wave-Particle Interaction Studies Poloidal array of energy and pitch/energy resolving detectors will measure ICRH tail ion fluxes escaping the plasma. D.C. Pace 1 , R.S. Granetz 2 , S.J. Zweben 3 , D.S. Darrow 3 , C. Fiore 2 , S. Wukitch 2 , A. Bader 2 , R. Parker 2 , J.H. Irby 2 , and M. García-Muñoz 4 1 ORISE, 2 MIT, 3 PPPL, 4 IPP Shot 1101216005 t = 0.86 s 1 MeV H + , v || /v = 0.1 Presented at the 2011 Alcator C-Mod Ideas Forum Plasma Science and Fusion Center, MIT January 10 - 12, 2011

Phase Space Measurements of Lost Energetic Ions Elucidate Behavior in the Core • Pitch (v || /v) and energy are measured by 1.5 imaging scintillator plates Shot 142111 t = 570 ms 1.0 • Narrow aperture causes scintillator strike position to be a function of energy and pitch 0.5 5 • Alfvén eigenmode (AE) analysis – lost orbits calculated from measurements z (m) 0.0 0 – simulation using measured AE properties identifies initially confined orbits that are placed on loss orbits due to the interaction* -0.5 5 • Significant contributor to Alcator C-Mod research -1.0 0 – ICRH efficiency and model validation FILD Confined – perturbation losses: sawteeth, ELMs, AEs Ion Lost Ion -1.5 5 – companion to CNPA (cross-constraining) 1.0 1.0 1.5 1.5 2.0 2.0 2.5 2.5 – high-Z wall performance R ( R (m) ) Contour represents a NOVA-K calculated TAE with n = 2 and peak Fast Ion Loss Detectors *M.A. Van Zeeland, et al., δ T e /<T e > ≈ 8 x 10 -3 , DIII-D. D.C. Pace, 2011 Alcator C-Mod Ideas Forum Phys. Plasmas , submitted (2010) et al., PPCF , submitted (2010) January 10-12, 2011

Scintillator Detectors are Sampled at 2 MHz, Capable of Resolving High Frequency MHD Activity • Energy selection is determined Ion Impacts Energy Resolving Unit by gold film thickness Film (shield, aperture not shown) Scintillator Glass • Construct/install five units Probe Shaft during 2011 vent Lens Fiber Optic • Pitch/energy resolving unit to follow (test on S 3 ) Mirror Film Size ~ 1 cm • Orbit modeling indicates LH-limiter as the ideal mounting position (facing B-port) • Up-to-date status information, /home/pace/lossDetector/cmod- lossDetector.pdf Fast Ion Loss Detectors 2011 Alcator C-Mod Ideas Forum January 10-12, 2011