1. The Heavy Ion Fusion Virtual National Laboratory Overview of Heavy-Ion Fusion Focus on computer simulation aspect* Computer Engineering Science seminar University of California at Berkeley May 4, 2004 Jean-Luc Vay (and many others from the) Heavy-Ion Fusion Virtual National Laboratory Lawrence Berkeley National Laboratory *This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Berkeley and Lawrence Livermore National Laboratories under Contract Numbers DE-AC03-76SF00098 and W-7405-Eng- 48, and by the Princeton Plasma Physics Laboratory under Contract Number DE-AC02-76CH03073

2. The Heavy Ion Fusion Virtual National Laboratory The U.S. Heavy Ion Fusion Program - Participation Lawrence Berkeley National LaboratoryMIT Lawrence Livermore National LaboratoryAdvanced Ceramics Princeton Plasma Physics LaboratoryAllied Signal Naval Research Laboratory National Arnold Los Alamos National LaboratoryHitachi Sandia National LaboratoryMission Research University of Maryland Georgia Tech University of Missouri General Atomic Stanford Linear Accelerator Center MRTI Advanced Magnet Laboratory Idaho National Environmental and Engineering Lab University of California a. Berkeley b. Los Angeles c. San Diego Employees of LBNL, LLNL, and PPPL form the U.S. Virtual National Laboratory for Heavy Ion Fusion

3. The Heavy Ion Fusion Virtual National Laboratory Outline Fusion energy –Principles, advantages/disadvantages –Basic requirements –Paths to fusion Heavy Ion Inertial Fusion –The target –The chamber –The accelerator –The source Modeling developments –New physics –New algorithms –Experiment/simulation interface –Data analysis Conclusion

4. The Heavy Ion Fusion Virtual National Laboratory FUSION ENERGY

5. The Heavy Ion Fusion Virtual National Laboratory FUSION ENERGY: principles

6. The Heavy Ion Fusion Virtual National Laboratory Equivalence of mass and energy Einstein’s equation –m = mass of particle –c = speed of light ~ 3.10 8 m/sec huge amount of energy can be extracted from mass conversion. Example: if a 1 gram raisin was converted completely into energy E = 1 gram x c 2 = (10 -3 kg) x (3.10 8 m/sec) 2 = 9.10 13 Joules ~ 10,000 tons of TNT!

7. The Heavy Ion Fusion Virtual National Laboratory Advantages of fusion Virtually inexhaustible resources of fuel (water) Clean (no CO 2 emission, almost no radioactive waste) Fusion reactors are inherently safe. They cannot explode or overheat. Byproducts or fuel cannot be used to build weapons of mass destruction The fuel is accessible worldwide Disadvantages of fusion Complex, still at conceptual stage Centralization of power sources

8. The Heavy Ion Fusion Virtual National Laboratory FUSION ENERGY: Basic requirements

9. The Heavy Ion Fusion Virtual National Laboratory Two fundamental forces at play Holds

10. The Heavy Ion Fusion Virtual National Laboratory In order to fuse, the nuclei have to overcome electrostatic barrier: go into the right direction: D T D out In T out Slice view3D view need energy (millions of degrees)need many events (many particles) Find these conditions in?Find these conditions in “PLASMAS”

11. The Heavy Ion Fusion Virtual National Laboratory States of matter

12. The Heavy Ion Fusion Virtual National Laboratory FUSION ENERGY: Paths

13. The Heavy Ion Fusion Virtual National Laboratory The different paths to fusion energy Tokamaks ITER Lasers (NIF) Particle accelerators “God’s way” “Human ways”

14. The Heavy Ion Fusion Virtual National Laboratory HEAVY ION INERTIAL FUSION

15. The Heavy Ion Fusion Virtual National Laboratory An Artist’s Conception of a Heavy Ion Fusion Power Plant From the overall system, we identify several parts and study them separately using theory, experiments and computer simulations.

16. The Heavy Ion Fusion Virtual National Laboratory HEAVY ION INERTIAL FUSION: the target

17. The Heavy Ion Fusion Virtual National Laboratory For symmetric illumination, the target is enclosed into a capsule Examples of capsule Hydrodynamic simulation of target implosion and capsule expansion (Lasnex) “hybrid” “close coupled”

18. The Heavy Ion Fusion Virtual National Laboratory LASNEX is validated against Laser fusion experiments

19. The Heavy Ion Fusion Virtual National Laboratory HEAVY ION INERTIAL FUSION: the chamber

20. The Heavy Ion Fusion Virtual National Laboratory Inside the chamber (Lasnex simulation) (Tsunami simulation)

21. The Heavy Ion Fusion Virtual National Laboratory Cut-away view shows beam and target injection paths for an example thick-liquid chamber

22. The Heavy Ion Fusion Virtual National Laboratory beam ions Flibe ions electrons target 3-D BPIC simulation of beam propagating through Flibe at 27.6 ns; 10 GeV, 210 AMU, 3.125 kA, 5x10 13 /cm 3 BeF 2

23. The Heavy Ion Fusion Virtual National Laboratory Does plasma neutralization really work? LSP simulations results for standard bismuth main pulse 1.2-mm waist is acceptable for distributed-radiator target

24. Unneutralized beamPartially neutralized beam Intensity in focal plane 400µA, 160 keV, Cs + Electrostatic quadrupole lenses for beam set-up Magnetic quadrupoles for final focusing Final-Focus Scaled Experiment studied effect of neutralizing electrons (from a hot filament) on focal spot size LSP particle- in-cell

25. The Heavy Ion Fusion Virtual National Laboratory HEAVY ION INERTIAL FUSION: the accelerator

26. The Heavy Ion Fusion Virtual National Laboratory Principles of particle accelerator AccelerationTransverse confinement (magnetic or electric) (SLAC)

27. The Heavy Ion Fusion Virtual National Laboratory High Current Experiment (HCX) began operation January 11, 2002. 10 ES quads ESQ injector Marx matching diagnostics

28. High-Current Experiment (HCX): first transport experiment using a driver-scale heavy-ion beam K +, 1 - 1.8 MeV, 0.2 - 0.6 A, 4 - 10 µs, 10 ES quads, 4 EM quads HCX is to address four principal issues: –Aperture limits (“fill factor”)? –How maximum transportable current affected by misalignment, beam manipulations, and field nonlinearities? –beam halo? –effects of gas and stray electrons? 9.44 m 2.51 m 3.11 m2.22 m1.38 m ESQ injectorMatching section10 ES quads end station diagnostics K+ source

29. The Heavy Ion Fusion Virtual National Laboratory 3-D WARP simulation of HCX injector

30. The Heavy Ion Fusion Virtual National Laboratory HEAVY ION INERTIAL FUSION: the source

31. The Heavy Ion Fusion Virtual National Laboratory 4 mA/cm 2 100 mA/cm 2 /beamlet Two possible ion source approaches Use a large diameter but low current density single-aperture ion source. (traditional) Extract hundreds of mm-scale high current density beamlets, from a multiple-aperture ion source. (experimental)

32. The Heavy Ion Fusion Virtual National Laboratory STS-500 investigating large-aperture diode dynamics Expt WARP Warp simulation Experimental results Risetime Phase Space at End of Diode

33. The Heavy Ion Fusion Virtual National Laboratory a RZ and transverse slice simulation used to understand parameter space and optimize design a 3D used for validation a Physics design with spherical plates completed; iterated with designer to ensure “buildability” 0.1.5 -7.5 7.5 0.51.0 Z (m) X (mm) Current = 0.07 Amps, Final energy = 400 keV Normalized emittance Physics design of 119-beamlet merging experiment on STS500 is complete

34. The Heavy Ion Fusion Virtual National Laboratory ParametersResultsStatus Current density 100 mA/cm 2 (5 mA)met goal EmittanceT eff < 2 eVmet goal Charge states > 90% in Ar + met goal Energy spread< a few % beam suffers CXmet goal Beamlets from Argon RF Plasma Source meet the required specifications Single Beamlet: Multiple Beamlet: RF Source: Image on Kapton:

35. The Heavy Ion Fusion Virtual National Laboratory Merging Beamlet fabrication is in progress Einzel Lens Test (STS-100) qualified high gradient insulator (up to 35 kV/cm). Full-gradient test (STS-500) vacuum gap voltage gradient (>100kV/cm) Soon

36. The Heavy Ion Fusion Virtual National Laboratory MODELING DEVELOPMENTS

37. The Heavy Ion Fusion Virtual National Laboratory Our next-step vision Beam Science  Inertial Fusion Energy Brighter sources/ injector Maximum, B n Transport Beam neutralization Theory/simulations Accelerator Final Focus Source and injector NOW NEXT STEP integrated beam experiment (IBX)...to test source-to-target- integrated modeling 3

38. The Heavy Ion Fusion Virtual National Laboratory The IBX mission is to demonstrate integrated source-to-focus physics 7m 25 ns 40 m (10 MeV) 15 m 250  25 ns 2 m 250 ns 1.7 MeV Ion: K + (1 beamline) Total half-lattice periods: 148 Total length: 64 m 5 - 10 MeV Injector Accelerator Drift Compression Final Focus Neutralization

39. The Heavy Ion Fusion Virtual National Laboratory We will develop an integrated, detailed, and benchmarked source-to-target beam simulation capability

40. The Heavy Ion Fusion Virtual National Laboratory MODELING DEVELOPMENTS: new physics

41. The Heavy Ion Fusion Virtual National Laboratory Electron production missing in simulation of HCX Beam head hit the structure

42. The Heavy Ion Fusion Virtual National Laboratory Toward a self-consistent model of electron effects Plan for self-consistent electron physics modules for WARP Key: operational; implemented, testing; partially implemented; offline development WARP ion PIC, I/O, field solve  f beam, , geom. electron dynamics (full orbit; drift) wall electron source volumetric (ionization) electron source gas module penetration from walls ambient charge exch. ioniz. n b, v b f b,wall  sinks nene ions Reflected ions f b,wall

43. The Heavy Ion Fusion Virtual National Laboratory WARP and electron cloud code POSINST merged the code POSINST, specialized in the prediction of electron clouds in high energy physics accelerator, was merged with WARP brings new capabilities and collaborations for study of electron clouds in heavy ion fusion and high energy density physics Specialized GUI page added to WARP GUI by UCB UG student –run POSINST –Read/plot output data

44. The Heavy Ion Fusion Virtual National Laboratory New large time-step electron mover reproduces the e-cloud calculation in < 1/25 time Full-orbit,  t=.25/f ce Large time-step interpolated A major invention that should have application to many fields including MFE, astrophysics, near-space physics...

45. The Heavy Ion Fusion Virtual National Laboratory MODELING DEVELOPMENTS: new algorithms

46. The Heavy Ion Fusion Virtual National Laboratory challenging because length scales span a wide range:  m to km(s) End-to-end modeling of a Heavy Ion Fusion driver mm m km

47. The Heavy Ion Fusion Virtual National Laboratory The Adaptive-Mesh-Refinement (AMR) method addresses the issue of wide range of space scales crosscutting example from CFD AMR concentrates the resolution around the edge which contains the most interesting scientific features. 3D AMR simulation of an explosion (microseconds after ignition)

48. The Heavy Ion Fusion Virtual National Laboratory Particle-In-Cell + AMR applied to HCX source in axisymmetric (r,z) geometry Low res. Medium res. High res. Medium res. + AMR Z (m) X (m) 4  NRMS (  mm.mrad) AMR-PIC simulation of ion source The high res. result is recovered with medium res.+AMR around beam edges at 1/4 of comput. cost

49. The Heavy Ion Fusion Virtual National Laboratory Collaboration HIF/CBP and ANAG (Phil Colella’s group) to provide AMR library of tools to Particle-In-Cell codes Example of WARP- Chombo injector field calculation

50. The Heavy Ion Fusion Virtual National Laboratory Vlasov Models offer low noise, large dynamic range x pxpx 10 -5 10 -4 10 -3 10 -2 10 -1 1 Solution of Vlasov equation on a grid in phase space Courtesy E. Sonnendrucker et al., IRMA, U. of Strasbourg with HIF-VNL Moving mesh Adaptive mesh

51. The Heavy Ion Fusion Virtual National Laboratory MODELING DEVELOPMENTS: interface experiment/simulation

52. We are using simulations to learn what data we need to take, and how best to use the data we obtain Simulations initialized using 4D particle distributions synthesized from ESQ-exit slit-scan data (simulated, here) are far better than those using an ideal distribution An (x,y) scan, in addition to (x,x) and (y,y), is important z (m) Normalized x emittance (  -mm-mr) semi-Gaussian Integrated simulation, starting at source 3-plane synthesis adding (x,y) data 2-plane synthesis using (x,x) and (y,y)

53. Optical slit diagnostic is yielding unprecedented information about HCX beam distribution isosurface where ƒ(x,y,x) = 30% of peak face-on (xy) view rotated to right ƒ(y,x) (integ. over x) line is mean x´(x=0) vs. y x´ y shadow of “bridge” across slit x u vy dz h This scanner measures f(x,y,x) It contains such information as the (y,y) distribution as a function of x, or averaged over all x It can be “gated” in time Phase-space diagnostics

54. The Heavy Ion Fusion Virtual National Laboratory MODELING DEVELOPMENTS: data analysis

55. The Heavy Ion Fusion Virtual National Laboratory Advanced interactive particle viewer High dimensionality (3-D X + 3-D V) data inherently difficult Collaboration with visualization group for developing new kind of particle viewer Interactive selection of particles is automatically translated to another view: A new rendering technique gives compact representation of 6-D data:

56. The Heavy Ion Fusion Virtual National Laboratory CONCLUSION Fusion is a very attractive source of energy –Would solve many problems –But hard to achieve Still far: there is lot of exciting science to study and technologies to develop Computer simulation plays a crucial role in studying science, planning and analyzing experiments The design of a full scale driver will rely heavily on integrated simulation from end-to-end In order to reach our goal, we are developing new state-of-the-art algorithms for computation and data analysis For more, visit our home page at http://hif.lbl.gov

57. The Heavy Ion Fusion Virtual National Laboratory BACKUP slides

58. The Heavy Ion Fusion Virtual National Laboratory 3D simulations of IBX z (m) in fixed-then-moving frame Beam created at source, matched, accelerated, begins to drift compress. Parameters: 1.7  6.0 MeV 200  100 ns 0.36  0.68 Amps 4.6 us of beamtime separating tail (  C/m) Mesh frozen Mesh accelerates with beam Drift compression

59. The Heavy Ion Fusion Virtual National Laboratory BASIC PLASMA COMPUTER MODELS

60. The Heavy Ion Fusion Virtual National Laboratory Computer simulation of plasmas We compute on various platforms: pc (Pentium, Athlon), Pentium clusters, IBM-SP IBM-SP very powerful parallel computer but need to simulate systems that contains at least 1000 billions of real particles Even on the NERSC IBM-SP, the simulation of all the real particles is usually unfeasible We have to make approximations!

61. The Heavy Ion Fusion Virtual National Laboratory Computer simulation of plasma as collection of particles –We use macroparticles (1 macroparticle = many real particles) –We compute the force (field) on a grid –We advance particle and fields by finite time steps xx yy

62. The Heavy Ion Fusion Virtual National Laboratory Computer simulation of plasma as fluid –A system containing many particles may (under certain conditions) be modeled as a fluid Example: air is made of molecules but is often described as a fluid –Restriction: one location = one velocity –We compute the fluid equation on a grid –The temporal evolution of the fluid is computed using finite time steps xx yy