FY WEP TSG Goals & WEP-Relevant Diagnostic Upgrades NSTX Supported by WEP TSG Meeting September 14,

WEP TSG FY Goals & Diagnostic UpgradesSeptember 14, 2011Introduction  Provide input on prioritizing diagnostics upgrades funded through the FY NSTX diagnostics collaboration  Final prioritization of NSTX diagnostic collaboration proposals will be based on input from ALL TSG’s  Discussion & prioritization for diagnostic collaborations should largely focus on research goals in the FY time frame: –B T (0) ~ T for 5 s –I p ~ 1 MA for 2-4 s & I p ~ 1.5 MA for 2-3 s –It will probably take ~ 2 years to achieve full performance (I p ~ 2 MA, B T (0) ~1 T) –n e < m -3 scenarios will probably predominate  RF experiments are presently under-diagnosed –Any diagnostic in HHFW area should get highest priority 2

WEP TSG FY Goals & Diagnostic UpgradesSeptember 14, 2011 Comments from 09/01/11 WEP TSG Discussion  May reduce the number of HHFW antenna straps from 12 to 8 (or maybe 6) following 2 years of operation, including operation at higher B T  Move implementation of upgraded *AE antenna one year earlier to FY2015  Because of longer pulse length and higher B T on NSTX-U need to double the EP diagnostic data acquisition rate and significantly increase data acquired each shot  NPA will need another location to view only one neutral beam line  Need a physics basis (mode numbers, frequency, structure, etc) before implementing an EHO antenna  EHO physics goals probably fit better with another TSG (T&T?)  High-density NSTX-U plasmas not ideal for active neutral beam diagnostics (eg. FIDA, NPA, ssNPA), however full B T & I p will not be achieved in NSTX-U until later campaigns in FY and low-density scenarios will still be possible 3

WEP TSG FY Goals & Diagnostic UpgradesSeptember 14, 2011 WEP TSG Research Goals 4 Run FY experiments in FY Year Plan Long-term WEP TSG Research Goals for FY :  Study effect of multiple, high frequency (>10 kHz), MHD modes and RF heating on fast-ion confinement  Use RF heating to enable fully non-inductive RF+NBI H-mode plasmas FY2011FY2012FY2013FY2014FY2015FY2016FY2017FY2018 Upgrade OutageNSTX-U Operation NSTX Diagnostic Collaboration

WEP TSG FY Goals & Diagnostic UpgradesSeptember 14, 2011 FY2014 Goals Energetic Particles:  Measure fast-ion redistribution with tangential FIDA, *AE eigenfunctions with BES and reflectometers [14-1]  Test capability of prototype *AE antenna & finalize design of upgraded *AE antenna to measure stability properties of *AEs & to compare damping rates from models & theory: - Excite CAE/GAE, a unique capability for NSTX-U RF-HHFW:  Heat low I p plasma, achieve high non-inductive current fraction, improve coupling to NBI-heated H-mode plasmas [14-2]  Evaluate possible alternate HHFW configurations during outage & perform tests using test stand (if funds are available)  Explore physics basis for particle transport induced by EHO excitation (eg. What mode numbers, frequency, structure etc. is needed for preliminary design?) RF-ECH:  Update design of ECH system plasma start-up support *EHO research goals probably fall within another TSG (T&T?) 5

WEP TSG FY Goals & Diagnostic UpgradesSeptember 14, 2011 FY2015 Goals Energetic Particles:  Use tangential + perpendicular FIDA to characterize distribution function modifications induced by *AE modes [15-1]  Measure *AE activity observed to be driven by more tangential 2 nd NBI - compare to existing more perpendicular NBI [15-2]  Implement upgraded *AE antenna RF-HHFW:  Heat CHI start-up plasma coupled to induction, sustain low I p plasma 100% non-inductively, improve coupling to NBI-heated H-modes[15- 3]  Assess HHFW performance at higher magnetic field and higher plasma density - especially compatibility with high-power NBI operations [15-4]  Design EHO antenna using HHFW straps, or some other location RF-ECH:  Implement short-pulse, high-power ECH system for plasma start-up support (0.5-1MW, 10-50ms) 6

WEP TSG FY Goals & Diagnostic UpgradesSeptember 14, 2011 FY2016 Goals Energetic Particles:  Optimization of *AE antennae design for efficient coupling to the plasma modes [16-1]  Simulate *AE activity driven by more tangential NBI, extend non-linear models to NSTX-U plasmas with 2 nd NBI, compare numerical and theoretical simulations to new data  Extend simulations of avalanches to FNSF/Pilot sustainment phase RF-HHFW:  Utilize HHFW to assist start-up plasma formation - compare to short- pulse ECH [16-2]  Assess impact of HHFW electron heating on NBI current ramp-up [16-3]  Simulate/mock-up performance using reduced number of straps  Implement EHO antenna compatible with HHFW requirements RF-ECH:  Test short-pulse, high-power ECH system for plasma start-up support and assess impact on close-flux current achieved, pulse-length extension, non-inductive fraction [16-4] 7

WEP TSG FY Goals & Diagnostic UpgradesSeptember 14, 2011 FY2017 Goals Energetic Particles:  Utilize *AE predictive capability to optimize/minimize *AE activity during non-inductive current ramp-up with 2 nd NBI. Compare simulations to experimental results [17-1]  Measure stability properties of high-f *AE with upgraded antenna [17- 2] RF-HHFW:  Modify HHFW antenna system to have reduced number of straps and test performance during I p ramp-up and NBI H-mode [17-3]  Test EHO antenna for impact on density/particle control RF-ECH:  Test upgraded ECH system power and pulse-length for EBW heating studies (1MW, s) [17-4] 8

WEP TSG FY Goals & Diagnostic UpgradesSeptember 14, 2011 FY2018 Goals Energetic Particles:  Assess requirements for "fast-ion phase-space engineering" techniques through selective excitation of *AE modes [18-1]  Extend simulations of *AE avalanches to FNSF/Pilot current ramp-up phase  Assess implications for FNSF/Pilot design, in particular NBI injection geometry, expected current drive RF-HHFW:  Utilize modified HHFW system heating and CD to optimize plasma start-up, ramp-up, and NBI sustainment [18-2] RF-ECH:  Pending successful EBW heating results, further upgrade ECH system power and pulse-length for EBW heating studies (2-4MW, 1- 5s),  Project EBW CD performance to FNSF/CTF 9

WEP TSG FY Goals & Diagnostic UpgradesSeptember 14, 2011 Proposed Diagnostics Upgrades that Support WEP Research Goals 10