LA-8000-C Proceedings of the Impact Fusion Workshop ~ National Security and Resources Study Center LOS Alamos Scientific Laboratory Los Alamos, New Mexico July 10—12, 1979 .-(a C --- > .- U3 g .- LOSALAMOS SCIENTI LABORATORY PostOfficeBox 1663 Los Alamos,New Mexico 87545 AI AffirmativeAction/~u61OpportunityEmployer Thisreportwasnoteditedby theTechnicalInformation staff. l%is report was Prep.red as a. account of work sponsored by the U“iled stat.. Govemmem. Netlher the Uruwd SUtes not the United St.tcs Department of Ener.v. nor any of their employees, nor any of their c.nw.cmts, s. bc. ntr.ctots. or their ●mp!oyecs, make. .ny warranty, express or implied. or .s. me. .“Y lecal Imbdtly or res!mnmbibty for the accuracY. completeness, or usefulness of ●ny mlormatl. n. apv.r.t.s, product. or Process dmclos.d, m rePrcsenls that Its use would not tnfcince Pnv. telY owned rights. uNITED STATES DEPARTMENT OF EN ERGV CONTRACT W-740 B-ENG. 36 LA-8000-C Conference UC-21 Issued:August 1979 Proceedings of the Impact Fusion Workshop National Security & Resources Study Center Los Alamos Scientific Laboratory Los A[amos, New Mexico July 10-12, 1979 Compiled by A.T. Peas[ee. Jr. Sponsored by the I Office of Research Policy U.S. Department of Energy I . .— Preface The Impact Fusion Workshop was held at the National Security and Resources Study Center of the Los Alamos Scientific Laboratory (IASL), Los Alamos, New Mexico, on July 10-12, 1979. Following this open Workshop, classified sessions were held on July 13, 1979. The Divisions of Research Assessment and of Advanced Technology Projects of the Office of Research Policy of the U.S.Department of Energy’s (DoE) Office of Research jointly sponsored the Workshop. Dr. R.N.Kostoff was the DoE Project Manager. The Workshop was planned and carried out as part of Field Tasks for the Evaluation of Impact Fusion Concepts at the University of Washington with Dr. F.L.Ribe as Principal Investigator and at the LASL with Dr. J.M.Williams as Contract Task Monitor. Dr. Ribe was the Technical Director of the Workshop. The purposes of the Workshop were to provide a forum for the exchange of ideas among those scientists and engineers who have expertise relevant to impact fusion and to arrive at a state-of-the-art description. The. results of the Workshop will form the basis for generating technical criteria to be used by the DoE in the assessment of impact fusion proposals. The Impact Fusion Workshop did not uncover any fatal flaws that rule out impact fusion. But neither did the Workshop discover any path of research and development that would definitely lead to impact fusion power generation. The Workshop determined the minimum projectile requirements for impact fusion to include a velocity of 200 kdsec with a kinetic energy of about 10 megajoules. The classified sessions of the Workshop did not alter these minimum projectile requirements. iv The Workshop started with overview presentations of three major topics: Target Dynamics, Reactor Systems, and Accelerator Systems. The overview presentations were followed by two days of detailed ● presentations, that reported theoretical and experimental work in progress, as well as conceptual presentations, that reported new ideas covering all three topics. Since there were no parallel sessions, an opportunity was provided for healthy interaction between participants whose interests covered more than one of the topics. These presentations were followed by Working Group Sessions for each of the three topics. The conclusions of the Working Groups follow. Target Interactions: In order to obtain a reasonable thermonuclear gain, one needs a plasma temperature of about 10 kilovolts, a plasma pressure of about 1000 megabars, and an ion density of about 3 x 1022 ions /cm3. A characteristic thickness of the macroparticle and plasma cavity might be a few millimeters, and the time scale of the thermonuclear burn might be 5 to 10 nanoseconds. A one half gram macroparticle with a velocity of 200 km/see, or 10 MJ of kinetic energy, may be able to provide these conditions. A major problem is to convert ● the linear kinetic energy into a three dimensional compression without energy losses that negate the efficiency advantages of three dimensional over one dimensional compressions. Calculations estimate an energy gain of more than 100 would require kinetic energy inputs of 10 megajoules for three dimensional compressions and 50 megajoules for one dimensional compressions. The corresponding projectile velocities are 130 and 500 kmlsec. An accelerator to drive a laser pellet must provide a velocity of 300 km/see. Reactor Systems: A reactor system with an energy per pulse of up to 100 gigajoules might be feasible with a fluid wall containment vessel with a radius of up to 10 meters. Duty cycles as short as one pulse every ten seconds may also be feasible. There are many problems, such as trajectory control and targeting, for which no solutions have been posed. Much more information on the basic performance requirements, such as target gain values for a range of target input energies, is neeeded before a system evaluation can be attempted. An overall system o engineering gain of four or five is needed before impact fusion will be v competitive with other forms of energy generation. Accelerator Systems: Four conceivable accelerator systems that might meet the minimum projectile requirements are the rail gun accelerator, the traveling magnetic wave accelerator, the ablative accelerator, and the plasma impulse accelerator: 1 Accelerator Type Efficiency Size2 Present Capability Rail Gun -20-50 % 140 meters3 3 gm @ 6 km/see Traveling Magnetic NIO-75 % 5 kilometers Tens of kgs @ Wave low velocities Laser Driven N5-10 z 140 meters3 Theoretical Ablative Plasma Impulse ~ 20% 140 meters3 Theoretical 1 Projectile kinetic energy / accelerator input energy. 2 For minimum projectile requirements. 3 Length determined by restricting the force on the projectile to below the elastic limit. 4 A proposed toroidal traveling magnetic wave accelerator might be much smaller. Considerable further evaluation of the last three accelerators is needed before proceeding with experiments. The two stage gas gun and the electrostatic accelerator systems very probably can not meet the minimum projectile velocity requirements. One hundred and nineteen scientists and engineers participated in the Impact Fusion Workshop. Fifty five represented fifteen States, the District of Columbia, and the United Kingdom. The remaining participants were from the LASL. A.T.Peaslee, Jr. LASL vi —Table —.of Contents Preface ................................................................e.i Impact Fusion Overview, R.N.Kostoff, Dept. of Energy, Presiding. Invited Papers: Scope of Impact Fusion @Revie~ ~Macrop~rticle Accelerators, F.L.Ribe and G.C.Vlases, Univ. of Washington ........................1 Z!?slYxDyn~ics e Thermonuclear !&% ~?.! J.Marshall, LASL ............... ● ......● .● ..... ● . ● . ● . ● . ● 20 - DYIIarniC~S!X!Thermonuclear Burn) part 11~ W. Chrlstlansen, Univ. of Washington ...............................30 Overview of Systems Requirements for Impact Fusion Power, J.M.filliams, L.A.Booth, and~A.Krakowski, LASL ...................44 Containment and Macroparticle Accelerators ~, R.E.Roberts, Dept. of Energy,~esiding. Invited Papers: Reactor Design Considerations for Inertial Confinement Fusion, L.A.Booth, LASL ...0..0.0 .............0.... ......0.. ...............0.. ..65 Fusion Impulse Containment, I.O.Bohachevsky, LASL .......................83 Blast Confinement Computations ——for the —Fast-Liner— Reactor (FLR), R.A.Krakowski, R.W.Moses, and J.D.Jacobson, LASL ..................107 Railgun Overview, R.A.Marshall, Univ. of Texas .........................128 Post Deadline Papers: Magnetic-Gun Igniter for Controlled Thermonuclear Fusion, R.L.Garwin, R.A.~ler, and B.Richter, SRI International ..........146 Impact Fusion with a Segmented Rail Gun, R.A.Muller, R.L.Garwin, and B. Richter, SRI International .........156 Counter-Rotating Disk Homopolar Generator(’’CRDHG”), R.L.Garwin, SRI International (Presented July 13,1979) ............164 Macroparticle Accelerators —II, J.P.Barber, International Applied Physics, Presiding. Invited Papers: Railgun Accelerators for Launching O.1-g Payloads ~ Velocities Greater —.Than 150 —km/s, R.S.Hawke, Lawrence Livermore Laboratory ...........167 DC Electromagnetic Launch Systems- Components ~ Technolo~~ — . I.R.McNab, D.W.Deis, and C.J.Mole, Westinghouse R&D Center. .......181 Electromagnetic Accelerator Concepts, H.H.Kolm, MIT Magnet Laboratory..206 Gas Dynamic Acceleration of Macroparticles to Very High Velocities, . — — F.Wlnterberg, Univ. of Nevada .....................................218 Rail Gun Powered by an Integral Explosive Generator, fi.Peterson and C.M.Fowler, LASL .................................234 Post Deadline Papers: Impact Fusion .of .the —Second —Kind: DT Fuelled Spheres Incident —on .a Passive Target, B.Maglich, Fu=on Energy Corp .....................245 Electrostatic Accelerators Revisited, J.F.Friichtenicht, TRW Space &Defense Systems Center ................................249 Macroparticle Accelerators 111, G.C.Vlases, Univ. of Washington, Presiding. Invited Papers: Models .of —Laser Ablative Acceleration for Impact Fusion, F.S.Felber, General Atomic Company ................................250 Laser Driven Macroparticles, J.S.DeGroot, Univ. of California, Davis, and T.E.McCann, USAF Academy ......................................268 Mass Accelerator for Producing Hypervelocity