On TAE’s Path to Fusion A Private-Sector Perspective Michl Binderbauer | President & CTO | TAE Technologies Committee on aCOMMITTE Strategic ON Plan A STRATEGIC for US Burning PLAN FOR Plasma U.S. BURNING Research, PLASMA General RESEARCH Atomic, | FEBRUARY Feb 26-28, 2018 2018 1 Agenda • Concept, Motivation and History • Key Past Program Accomplishments • Current Status and Next Steps • Overall Perspective Forward – Public-Private Partnership COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 2 TAE Concept Advanced beam driven FRC • High plasma β~1 • compact and high power density • aneutronic fuel capability • indigenous kinetic particles • Tangential high-energy beam injection • large orbit ion population decouples from micro-turbulence • improved stability and transport • Simple geometry • only diagmagnetic currents • easier design and maintenance • Linear unrestricted divertor • facilitates impurity, ash and power removal COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 3 Goals, Issues and Initiatives for FRC Research FESAC TAP report (2008) & ReNeW (2009) Long-range mission • Develop compact (high-β) reactor without toroidal field coils or a central solenoid ITER era goal • Achieve stable, long-pulse keV plasmas with favorable confinement scaling Key issues • Is global stability possible at large s (a/ρi ≥ 30) with low collisionality? • What governs energy transport and can it be reduced at high temperature? • Is energy-efficient sustainment possible at large-s and with good confinement? • Theory and simulation challenges (high-β, kinetic effects, transport) Suggested possible initiatives • Build larger facility with rotating magnetic fields or neutral beam injection (NBI) • Develop comprehensive diagnostics suite (profiles, fluctuations, …) COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 4 TAE’s Goals to Now Test for failure early and at lower cost while reducing most critical risks Establish beam driven high-β FRC physics test beds to • provide fast learning cycles and large experimental dataset (close to 60,000 shots) • demonstrate sustainment via Neutral Beam Injection (NBI) for >5 ms discharges (longer than critical timescales) with high repeatability • study tangential NBI and fast particle effects on stability and transport • measure scaling and study fluctuations and transport • assess potential for current drive, power balance and its implications Provide opportunity to • tightly integrate theory/modeling with experimentation • develop engineering knowhow and integration Invite collaboration to accelerate progress • Budker Institute, PPPL, UCI, UCLA, LLNL, Univ. of Pisa, Univ. of Wisconsin, Nihon Univ., Univ. of Washington, Google, Industrial partners COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 5 Past TAE Program Evolution A & B – Basic FRC core C-2 – HPF* w/ 2 guns, Ti getter C-2U – Sustainment 5+ ms n 100-800 G, 5-10 eV n 1 kG, 1 keV n 1 kG, 1 keV n ion beams, Wb ~0.1 kJ n neutral beams, Wb ~12 kJ n neutral beams, Wb ~100 kJ * HPF – High Performance FRC regime C-1 – Enhanced lifetime C-2 – HPF* w/ 2 guns, Li getter n 400 G, 10 eV n 1 kG, 1 keV n ion beams, Wb ~1 kJ n neutral beams, Wb ~20 kJ COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 6 Key Past Program Accomplishments COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 7 Global Stability Control via Edge Biasing • Active and passive bias electrodes “communicate” with FRC separatrix via scrape-off layer • Generate inward Er to counter FRC spin-up, and stabilize rotational modes (e.g. n=2) in axisymmetric way • Line-tying between FRC and plasma gun stabilizes wobble (provided that sheath resistance Bias: On/Off Plasma Gun: On/Off is low) Binderbauer, et. al, Phys. Plasmas 22, 056110 (2015) COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 8 Advanced Beam Driven FRC Enabled by Fast Ions 5 • Fast ion confinement near classical limit 4 !i ~ (1-2) !icl 3 2 • Total pressure is maintained, while thermal .1 e 1 pressure is replaced by fast ion pressure, up to Measured lifetime [ms] Pfast/Pth ~ 1 0 mb20141119.ta 0 1 2 3 4 5 Classical slowing down time [ms] • Global modes are further suppressed • Lifetime increases with NBI 1.0 6 NBs 5 NBs 4 NBs 3 NBs 0.5 2 NBs 1 NB Plasma Radius 0.0 0 1 2 3 4 5 6 7 8 9 10 11 Time (ms) Binderbauer, et. al, Phys. Plasmas 22, 056110 (2015) COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 9 FRC Sustainment Correlates with NBI , et., al, AIP Conf. proceedings (2016)030003 1721, • Pulse length limited by hardware and stored energy supply (biasing, beams) Binderbauer • Flux maintained up to at least 5-5.5 ms – showcases ability to drive current M. COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 10 Driftwave Stable Core, Unstable Scrape-off layer Density fluctuation Linear dispersion (experiment)* (simulation) –1 10 0.82≤r/Rs≤0.87 FRC core 1.10≤r/Rs≤1.22 SOL 10–2 ~ n/n 10–3 10–4 0 15 30 45 60 75 Schmitz, et. al, Nat. Comm. 7, 13860 (2016) 13860 7, Comm. Nat. al, et. Schmitz, kζ ρs kζ = n/R κ=R0/Ln (normalized inverse density scale-length) ρs=√((Ti+Te)/mi) COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 11 Critical SOL Gradient Controls Onset of Fluctuations Density fluctuation Linear dispersion (experiment)* (simulation) r/Rs ~ 1.15 (SOL) r/Rs = 0.95 0.04 (Core) r/Rs ~ 0.85 kθρs ~ 5–20 (2017)082512 24, ñ/n 0.02 0 2 3 4 R/Ln Lau, et. al, Phys. Plasmas (R0/Cs = 2.5 μs) R/Ln crit R/Ln crit κ=R0/Ln (normalized inverse density scale-length) COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 12 19 –3 ne (10 m ) 0.6 2.3 Fluctuation Suppression via 1.9 0.4 0.2 1.5 1.1 (m) 0 E×B Sheared Flow r 0.2 0.7 0.4 0.4 R Rs 0.6 0 0.14 • (au) Strong E×B shearing rate due to plasma 0.07 r/Rs=1.1 ñ/n r/Rs=0.9 gun biasing 0 6 n R/Ln crit r/Rs=1.1 4 R/L 2 • Sheared E×B flow upshifts critical r/Rs=0.9 gradient and reduces turbulence via 1.0 ad/s) r 0.5 eddy shearing/decorrelation 6 (10 D , B 0 x E r (cm) f • Radial transport barrier at/outside the 3.0 –0.5 separatrix 1.5 1.5 1.0 0 (cm) r –10 0 10 (2016) 13860 7, Comm. Nat. al, et. Schmitz, 0.5 r-Rs (cm) 0 0 0.5 1.0 1.5 2.0 2.5 Time (ms) COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 13 Dramatically Improved Confinement CP10.00064 (2016) CP10.00064 . Am. Phys. Soc. 61, 61, Soc. Phys. Am. , et., al, Phys. Plasmas (2015)056110 22, PBull • ~10× improved particle • Strong positive correlation between Te Binderbauer confinement and τEe Trask,et. al, • Good fit – ⌧ T 2.3 Ee / e COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 14 Past TAE Program Evolution • Fast ion confinement is close to classical • Quiescent Core • Stabilized by FLR effects, magnetic well, fast electron parallel dynamics • Inverted wavenumber spectrum – evidence of FLR stabilization of ion modes – consistent with near-classical core thermal ion transport • Some electron-scale turbulence – anomalous electron transport (χe < 20 χcl) • τEe exhibits positive Te power dependence • SOL/Edge Fluctuations • Fluctuations peak outbound near separatrix, with radial outbound convection • Exponentially decaying gyro-scale turbulence up to kθρs < 50 • Critical density gradient controlls onset of density fluctuations • Core and SOL coupling – SOL turbulence affects FRC confinement • Evidence of localized flow shear at separatrix creating thermal barrier COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 15 Current Status and Next Steps COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 16 TAE progress towards fusion Evolutionary sequence of platforms TAE’s current Major development platforms integrate then machine best design • First plasma July 2017 • incremental bases for rapid innovation • One year construction • On time, on Copernicus entering phased sequence of budget reactor performance experiments C-2U Plasma Sustainment A, B, C-1 200’ Early development and C-2 science First full-scale machine 100’ 70’ Norman Copernicus Reactor plasma performance 70’ (aka C-2W) Collisionless Scaling 1998 – 2000s 2009-2012 2013-2015 2017-2018 2019+ COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 17 Norman Goals Explore beam driven FRCs at 10x stored energy compared to C-2U • Principal physics focus on • scrape off layer and divertor behavior • ramp-up characteristics • transport regimes • Specific programmatic goals • demonstrate ramp-up and sustainment for times well in excess of characteristic confinement and wall times • explore energy confinement scaling over broad range of parameters • core and edge confinement scaling and coupling • consolidated picture between theory, simulation and experiment • develop and demonstrate first order active plasma control COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 18 Norman (aka C-2W) TAE’s 5th generation machine Magnetic Field 0.1–0.3 T Plasma dimensions – rs , Ls 0.4, 3 m 19 -3 Density – ne 3×10 m COMMITTE ON A STRATEGIC PLAN FOR U.S. BURNING PLASMA RESEARCH | FEBRUARY 2018 19 Temperature – Ti ,Te 1-2, 0.2-1 keV Norman – Neutral Beam System Norman Norman C-2U Phase 1 Phase 2 Beam Energy, keV 15 15 15/15-40 Total Power 10 13 21 # of Injectors 6 8 4/4 Pulse, ms 8 30 30 Ion current per source, A 130 130 130 • Centered/angled/tangential neutral-beam injection • angle adjustable in range of 15°–25° • injection in ion-diamagnetic (co-current) direction • High current with low/tunable beam energy • reduces peripheral fast-ion losses • increases core heating / effective current drive • rapidly establishes dominant fast-ion pressure for ramp-up COMMITTE ON A STRATEGIC PLAN FOR U.S.