Status of Fusion Energy Science Research at Los Alamos

Summary

This presentation summarizes the status, priorities, and experimental highlights of the Fusion Energy Sciences (FES) and High Energy Density Laboratory Physics (HEDLP) programs at Los Alamos National Laboratory as of late 2010. Key topics include LANL’s contributions to the ITER fuel cycle, laser-driven ion beam fast ignition on Trident, Magnetized Target Fusion (MTF) experiments on FRCHX at AFRL, construction of the Plasma Liner Experiment (PLX), and diagnostic support for the National Ignition Campaign at NIF.

Slide 1: Title Slide

Status of Fusion Energy Science Research at Los Alamos

G. A. Wurden

Fusion Power Associates Symposium Fusion Energy: Status & Prospects Washington DC

Dec. 1, 2010

LA-UR-10-07972 UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA Slide 1

Slide 2: Outline

OUTLINE

• General information on Fusion Energy Sciences Program at LANL • Contributions to ITER • Fast Ion Generation experiments on Trident • Magnetized Target Fusion (MTF) Experiments FRCHX at AFRL • Plasma Liner Experiment (PLX) construction • Contributions to NIF National Ignition Campaign

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Slide 3: Fusion Energy Sciences (FES)

Fusion Energy Sciences (FES)

Priorities at LANL: • Three legs: Theory & simulation, Experiment, and Engineering • Fusion Simulation Program (FSP) • High Energy Density Laboratory Physics (HEDLP) • Basic plasma science, including joint fission fusion materials facility (FFMF) • Supporting roles on FES machines around the nation and world, and at ITER

Changes for FES FY2011: ($5.1MFY11BA+$1.29M ITER) • Two important off-site collaborations in MFE: Alcator C-Mod and W7X stellarator • The ReNeW HEDLP report is available (Trident on its cover), magnetized HEDLP in Chapter 2 • Finishing an ITER intense neutron source design (with South Korea) for diagnostic calibrations • Preparing proposals for HEDLP science call • Submitted proposal 7/1/2010 for a US fusion materials irradiation facility preconceptual study • Preparing inputs to the NAS IFE panel • New ITER-IO contract proposals submitted, two early career FES science proposals submitted

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Slide 4: Fusion Energy Science 2010 LANL Highlights

Fusion Energy Science 2010 LANL Highlights

Research: • ITER work is ongoing, but the pace has been reduced for FY11 • The first engineering test shot of the full FRC/Shiva Star magnetized target fusion experiment occurred on April 16, 2010. It was an engineering success (all subsystems worked correctly), but the captured plasma decayed too quickly. We have investigated why, and checkout testing prior to the next shot is in progress. • The Plasma Liner Experiment construction is proceeding in its test bay. A large 9-ft diameter vacuum chamber and control systems are in place. • A new ICC collaboration on the W7X stellarator, with PPPL and ORNL, starting FY11. • Two of our ICC projects were terminated (Inertial Electrostatic Confinement (IEC) and U-Washington collaboration on FRC’s). Three new proposals were not funded. • A new HEDLP experiment with UC Davis to develop beat wave magnetic field generation. • Theory work ongoing (you will hear about the Fusion Simulation Project later)

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Slide 5: ITER fuel processing challenges

ITER fuel processing challenges

• Scale-up – 20x throughput – 20x inventory – 20x shorter processing time • Melding tritium handling/safety approaches • Requirements uncertainty • Tritium is a limited resource

[email protected]

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Slide 6: LANL ITER fuel cycle contributions

LANL ITER fuel cycle contributions

• Tokamak Exhaust Processing system - with SRNL – Design, R&D, Chemical flow sheet modeling • Overall Fuel Cycle – Integration, commissioning plans, schedule – Tritium Plant, hazard analysis • Test blanket module – Tritium extraction – processing

[Includes TEP Process Flow Diagram]

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Slide 7: HEDLP Fast Ignition with laser-driven ion beams

HEDLP Fast Ignition with laser-driven ion beams

Juan C. Fernández LA-UR-10-07520

presented @: APS DPP Conference Chicago, Illinois November 8 — 12, 2010

TRIDENT national user program: Enabling World-Class Science in High-Energy Density Physics

[Diagram: Laser pulse on 30 nm Laser Target generating Neutralized Ion Beam]

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Slide 8: Quasi-monoenergetic low-Z ions as fusion ignitor beam

Quasi-monoenergetic low-Z ions (e.g., C) have potential advantages as a fusion ignitor beam.

• Potential advantages over electron* or proton-based¹ FI: – Quasi-monoenergetic-ion source may be placed far from the fuel – Sharper deposition (higher efficiency) – Most robust particle-beam transport – Many fewer ions than protons required

• Potential issues: – Demo ~ 400 MeV ± 10% C beam – Laser – ion conversion efficiency: ~ 10% desired & observed – Focusing C ion beam: only proton focusing demonstrated

Comparison Table:

• Protons: Energy = 7 – 19 MeV, Number of Ions = ~10¹⁶, Laser Intensity = ~ 10²⁰ (TNSA) W/cm², Minimum areal densities, layer thickness @ 0.1 mm² = 10¹⁸ cm⁻², ~ 2 µm (CH)
• C⁶⁺: Energy = 400-480 MeV, Number of Ions = ~10¹⁴, Laser Intensity = ~ 10²¹⁻²² (BOA, RPA) W/cm², Minimum areal densities, layer thickness @ 0.1 mm² = 10¹⁶ cm⁻², ~ 10 nm

• Tabak et al., PoP 1, 1626 (1994); ¹ Roth et al., PRL 86, 436 (2001); ² D. Clark & M. Tabak, Nucl. Fus. 24, 1147 (2007)

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Slide 9: C acceleration results

C acceleration: achieved separately high energy¹, low energy spread, high efficiency.*

Results: • Demonstrated ~ 500 MeV energies (Trident)

[Plots showing energy spectra: 2D VPIC C, protons, off-axis C, on-axis C; Analytical model vs. Exp Cutoff Energy in BOA-Regime and TNSA-Regime; 3D-VPIC simulation at 10²¹ W/cm², 152 fs, 30nm DLC foil]

¹ B. M. Hegelich, et al., Subm. Nature Physics, (2010)

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Slide 10: HEDLP Magnetized Target Fusion, LANL/AFRL FRCHX

HEDLP Magnetized Target Fusion, LANL/AFRL FRCHX

Our first full-up systems test was April 16, 2010. An engineering success, with interesting physics, but a failed compression. The second shot in this series is being readied & tested now.

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Slide 11: FRCHX Team (April 2010)

FRCHX Team (April 2010)

C. Grabowski, J. H. Degnan, D. J. Amdahl, R. Delaney, M. Domonkos, F. M. Lehr, P. R. Robinson, E. L. Ruden, W. White, H. Wood Air Force Research Laboratory, Directed Energy Directorate, Kirtland AFB, NM 87117, USA

D. Brown, D. Gale, M. Kostora, J. McCullough, N. Montano, J. Parker, W. Sommars SAIC, Albuquerque, NM 87106, USA

M. H. Frese, S. D. Frese, J. F. Camacho, S. K. Coffey, V. Makhin NumerEx LLC, Albuquerque, NM 87106, USA

T. P. Intrator, G. A. Wurden, J. Sears, P. J. Turchi, and W. J. Waganaar Los Alamos National Laboratory, Los Alamos, NM 87545, USA

R. E. Siemon, B. S. Bauer, S. Fuelling University of Nevada, Reno, Reno, NV 89557, USA

A. G. Lynn, N. F. Roderick University of New Mexico, Albuquerque, NM 87131, USA

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Slide 12: Overview of FRCHX

Overview of FRCHX

• Grabowski, Degnan, et al., APS-DPP 2010 posters

Integrated Technologies: • FRC formation, translation, and capture • Solid liner implosions MHD modeling in concert with electromagnetics modeling yields end-to-end simulation with high correlation to experimental hardware • Pulsed power, plasma, and neutron generation diagnostics

Description: • Magnetized plasma compression provides an intermediate and low cost approach to HED plasmas • One application: magneto-inertial fusion pathway between ICF and MFE • Compact toroid (CT) insulates dense hot plasma from low temperature impurity species • Field reversed configuration is an attractive CT • Liner implosion to drive compression and heating of the FRC

Research Areas: • In-depth study of the fundamentals of physics of HED laboratory plasmas in the presence of high magnetic fields ◊ Magneto-inertial fusion ◊ Studies of particle transport in highly magnetized, dense plasmas ◊ FRC Plasma instabilities

Slide 12

Slide 13: Choosing the FRC

Choosing the FRC

• Advantages of FRCs for HED plasmas: – Simple cylindrical geometry – High β (β ~ 1) and high power density → compact system – Translatable → formation and adiabatic heating regions can be separated – Natural separatrix diverter – isolation from walls, impurity barrier

[Includes density contours at t = 7.70004E-06, 9.00033E-06, and 1.30002E-05 s, and schematic of Plasma Injector and Liner Implosion System]

Slide 13

Slide 14: FRC Translation

FRC Translation

• The FRC is ejected from the formation region by J x Br forces • Fields along the short translation region keep the FRC from expanding • Lower and Upper mirror fields form a capture region for the FRC that stops it within the center of the liner

[Schematic showing Formation in Conical Theta Coil, Translation, Capture, ~1 m scale]

Slide 14

Slide 15: Target Plasma Parameters

Target Plasma Parameters

• Present and Projected FRC Parameters – In formation region of experiment – n ~ 10¹⁷ cm⁻³ – T ~ 100 – 300 eV – Poloidal B ~ 2 - 5 T – After solid liner compression – n > 10¹⁹ cm⁻³ – T → several keV – Poloidal B ~ 200 - 500 T • Energy confinement time > 10 µs needed, 20 µs desired

Slide 15

Slide 16: FRCHX Test Milestones Past 12 Months

FRCHX Test Milestones Past 12 Months

Slide 16

Slide 17: B-dot Probe Measurements Formation Region

B-dot Probe Measurements Formation Region

• Axial magnetic probe signal shows field vs. time from Bias, Cusp, Pre-Ionization, and Main Theta discharges. • All discharges except that of the Cusp are through the 10-segment Theta coil.

[Plot: Axial Magnetic Flux Density Measured at F and J Segments of the Theta coil at the quartz tube outer radius (Test 6, 16 Mar 2010), showing Bias field rising, Cusp field applied, Pre-Ionization, Main field applied, and Main field crowbarred]

Slide 17

Slide 18: Overview: Formation, Translation, Capture Results with Extended Quartz Tube

Overview: Formation, Translation, Capture Results with Extended Quartz Tube

• Field exclusion lifetimes of captured FRCs were 6 to 10 µs – This is sufficient for injection and capture tests but considerably short for compression of closed field line configuration. – The lifetime was, however, deemed adequate for an engineering test of the overall formation, translation, capture, and compression system. • Density path integral was ~ 2 x 10¹⁷ cm⁻² in the capture region • Lifetime of this density exceeded 20 µs – This was in range of interest for a compression experiment. • Inferred temperature from exclusion radii, field pressure, and density was ~ 200 to 300 eV – This was also in the range of interest for compression experiment.

Slide 18

Slide 19: MHD simulation on liner radius vs time

MHD simulation using experimental current agrees with radiography on liner radius vs time

NumerX MACH2 results for Shiva Star liner compression for 2 Tesla initial axial magnetic field. Calculated peak field is 540 Tesla.

[Plot showing Time (s) vs. Radius (m), Bz (T), Circuit current (A), Te (eV), and ρ (kg/m³), comparing liner inner and outer radii from radiographs with simulated parameters]

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Slide 20: Implosion Radiography

Despite heavy debris damage to digital film we obtained useful radiograph

Implosion - compression experiment radiograph obtained at 22.985 µs after start of implosion discharge current indicates that liner imploded symmetrically, with little or no instability growth, and achieved 11 times radial compression of inner surface. Faraday rotation and inductive current probes indicated ~ 11 MA implosion current with 10 µs rise time.

[Includes current plot showing ~11 MA peak and radiographic images comparing Setup liner edge (10 cm) to Shot liner edge (0.89 cm inner, 2.38 cm outer)]

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Slide 21: Aug 2010 – Present Test Setup

Aug 2010 – Present Test Setup

FRCHX under the Shiva bank (Nov. 2010).

[Diagram of FRCHX diagnostics layout showing B-dot probes (T0 to T6), Flux Loops, Optical Fibers, and Interferometers across Formation, Translation, and Capture stages; Photo of FRCHX under Shiva bank]

Slide 21

Slide 22: B-dot Probe Measurements: Guide Field Matching Compression-Heating Test

B-dot Probe Measurements Guide Field Matching Compression-Heating Test

• Strong T6 signal observed. • Secondary peaks on T4 and T3 signals after the first T6 peak; secondary peak on T6 signal, as well. • At least some plasma captured; elasticity of the FRC allowing it to stretch beyond the upper mirror while a portion remains trapped between the mirrors.

Test Parameters (Sept 01, 2010 test 09): Main: ±35 kV; PI: 65 kV; Bias: 5.6 kV; L. Cusp: 2.4 kV; G/M: 2.8 kV; Pre-fill: 50 mTorr. T0 signal is inverted.

Slide 22

Slide 23: FRCHX Test Summary

FRCHX Test Summary

• Numerous FRC formation, translation, injection, and capture experiments have been conducted to characterize FRC T, n, and lifetime with FRCHX. • Three capture region configurations have been implemented: – An extended quartz tube through the capture region to facilitate diagnostic access – The complete compression-heating hardware configuration – A mock up of the liner with modified upper electrode and top flange to allow B-dot probe insertion into the liner • Plasma T and n have typically been 200300 eV and 10¹⁶10¹⁷ cm⁻³, respectively; trapped flux lifetimes have been only been 6~10 µs in duration. • MHD simulations are being closely coupled to the experiment to aid in improvements. • The first full-up implosion test (April 16, 2010) was an engineering success • Second implosion experiment is ready, and is being statically tested now, to be dynamically imploded in Jan 2011. • We are working on longer trapped FRC lifetimes, through higher bank settings, better trapping, more uniform preionizaiton. Further modifications will be implemented in subsequent tests in FY11.

Slide 23

Slide 24: Plasma Liner Experiment (PLX)

Plasma Liner Experiment (PLX) will merge 30 plasma jets to create cm and µs scale plasmas approaching HED conditions (~0.1 Mbar)

• Scientific goals: predictive understanding of jet propagation/merging, spherical plasma liner formation/convergence/stagnation, and “standoff” magnetization • Motivations: enable platform for discovery-driven HEDLP science, especially magnetized HEDP, and standoff embodiment of magneto-inertial fusion • Status: Phase 1 construction nearing completion with first experiments in 2011

Drawing by David Van Doren, HyperV

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Slide 25: PLX Motivation and Astrophysics Applications

Motivation: PLX can study transport/stability in magnetized HED plasmas and field unique laboratory plasma astrophysics experiments

• PLX can study transport in M-HED plasma (unmagnetized vs magnetized transport regimes) • PLX can span linear stability thresholds for magnetic Rayleigh-Taylor instability • An experiment to generate a rotating plasma disk and (hopefully) emergent axial jets • An experiment to generate both magnetized and unmagnetized collisionless shocks

CAD by David Van Doren, HyperV

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Slide 26: National Ignition Campaign Activities at NIF

LANL is engaged in National Ignition Campaign activities at the NIF

• LANL has ~35 people working in the Inertial Confinement fusion program • LANL has four employees that spend > 75% of their time at LLNL working at the NIF with several more spending a significant amount of time at LLNL – Designing, leading, and participating in experiments, as well as installing diagnostics – LANL personnel lead the fielding of the symmetry experiments this fall up to 1.3 MJ* • LANL is building two key nuclear diagnostics for ignition – Gamma Reaction History to measure the burn history and bang time of the capsule implosion – Neutron imaging to measure the shape of the burning fuel

*Invited talks at the APS-DPP by John Kline and George Kyrala First three gas cells for GRH installed on the NIF chamber

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Slide 27: Conclusions

Conclusions

• It is an exciting time to be doing Fusion and HEDP research. • We look forward to contributing to the NAS IFE Review, through all forms of our IFE-related work. • We are on a good path for the next several years, and hope that the course can be maintained, and even accelerated.

[Poster: Physics Research Career Opportunities at Los Alamos - Discovery, Science, Innovation, Exploration; [email protected]]

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