PLASMA PHYSICS AND CONTROLLED NUCLEAR FUSION RESEARCH 1982 VOL. II NUCLEAR FUSION SUPPLEMENT 1983 PROCEEDINGS OF THE NINTH INTERNATIONAL CONFERENCE ON PLASMA PHYSICS AND CONTROLLED NUCLEAR FUSION RESEARCH HELD BY THE INTERNATIONAL ATOMIC ENERGY AGENCY IN BALTIMORE, 1-8 SEPTEMBER 1982 In three volumes INTERNATIONAL ATOMIC ENERGY AGENCY, VIENNA, 1983 STI/PUB/626 ISBN 92-0-130183-9 FOREWORD Considerable progress towards demonstrating the feasibility of controlled fusion as well as economically favourable fusion reactor characteristics was reported at the Ninth IAEA Conference on Plasma Physics and Controlled Nuclear Fusion Research. This progress extends to all approaches to controlled fusion and fusion technology. The Conference was organized by the Agency in co-operation with the United States Department of Energy, with the assistance of the Princeton Plasma Physics Laboratory. It took place on 1-8 September, 1982, in Baltimore, Maryland, USA, and was attended by 488 participants and 145 observers from 31 countries and five international organizations. One hundred and forty-seven papers were presented at the technical sessions, including two poster sessions. They included contributions on theory, open and closed magnetic confinement systems, inertial confinement systems, and related technology. The traditional Artsimovich Memorial Lecture was given at the beginning of the Conference. These Proceedings, which include all the technical papers and four conference summaries, are published in English as a supplement to the IAEA journal, Nuclear Fusion. CONTENTS OF VOL. II - TOKAMAK EXPERIMENTS II (Session I) - PLASMA HEATING II (Session J) - POST-DEADLINE PAPERS (Session K) - STELLARATORS, BUMPY TORI, MULTIPOLES I (Session L) - HIGH-BETA SYSTEMS II (Session M) - INERTIAL CONFINEMENT III (Session N) - TECHNOLOGY AND REACTOR CONCEPTS II (Session O) - POSTER SESSION (Session V) HIGH-POWER ICRF AND ICRF PLUS NEUTRAL-BEAM HEATING ON PLT D. Hwang, M. Bitter, R. Budny, A. Cavallo, R. Chrien, S. Cohen, P. Colestock, C. Daughney, S. Davis, D. Dimock, P. Efthimion, H. Eubank, D. Gambier, R. Goldston, D. Herndon, E. Hinnov, J. Hosea, J. Hovey, R. Kaita, D. Manos, E. Mazzucato, D. McNeill, D. Mikkelsen, D. Mueller, A.L. Pecquet, D. Post, G. Schilling, C. Singer, J. Strachan, S. Suckewer, H. Thompson, S. von Goeler, J. Wilson Plasma Physics Laboratory, Princeton University, Princeton, New Jersey, USA Abstract: PLT ICRF experiments with RF powers up to ~3 MW have demonstrated efficient plasma heating in both the minority fundamental and the second harmonic ion-cyclotron regimes. In the minority 3He regime, ion temperatures of ~3 keV have been produced along with ~1 kW of D-3He fusion power and substantial electron heating. In the second harmonic H regime, an equivalent averaged ion energy of ~4 keV has been achieved. Combined ICRF plus neutral-beam heating experiments with auxiliary powers totalling up to 4.5 MW have provided insight into auxiliary heating performance at stored plasma energy levels up to ~100 kJ. DOMINANT ROLE OF WAVE CONVERSION MECHANISM IN TFR ION CYCLOTRON HEATING EXPERIMENTS Equipe TFR, Association Euratom-CEA sur la fusion, Fontenay-aux-Roses, France Abstract: Experimental evidence demonstrating the essential role played by the wave conversion layer in TFR ICRF experiments is reviewed: the mode structure of the wave in the torus, the conditions for efficient heating of both ions and electrons, local generation of the slow wave as evidenced from the scattering of a laser beam, and ejection of a third ion species in the prescribed conditions lead to a general agreement with theoretical schemes. ENERGY AND IMPURITY TRANSPORT IN THE ALCATOR C TOKAMAK B. Blackwell, C.L. Fiore, R. Gandy, A. Gondhalekar, R.S. Granetz, M. Greenwald, D. Gwinn, E. Källne, J. Källne, S.E. Kissel, B. Lipschultz, N.G. Loter, E.S. Marmar, S. McCool, D. Overskei, D.S. Pappas, R.R. Parker, R. Petrasso, M. Pickrell, P.A. Politzer, M. Porkolab, P. Pribyl, J.E. Rice, F. Seguin, J.J. Schuss, J.L. Terry, R. Watterson, S.M. Wolfe Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA Abstract: Energy and impurity confinement times, tau_E and tau_I, have been investigated in Ohmically heated Alcator C discharges. Geometrical dependences have been studied by operation with full circular apertures of various major and minor radii, R, a_L. At n_bar = 2 x 10^20 m^-3, the results of size-scaling experiments are summarized by the relation tau_E proportional to a_L^0.8 R^2.3. Impurity confinement studies using the laser blow-off technique show tau_I independence of charge and mass of the injected impurity, linear dependence on a_L, rapid deterioration with m=2,3 tearing modes, and linear dependence on effective charge. LOWER-HYBRID HEATING EXPERIMENTS IN THE FRASCATI TOKAMAK (FT) F. Alladio, M.L. Apicella, E. Barbato, G. Bardotti, R. Bartiromo, F. Bombarda, G. Bracco, G. Buceti, P. Buratti, R. de Angelis, F. de Marco, M. de Pretis, D. Frigione, M. Gasparotto, R. Giannella, M. Grolli, M. Haegi, A. Mancuso, V. Merlo, V. Pericoli, L. Pieroni, S. Podda, E. Purchi, J.P. Rager, G.B. Righetti, F. Romanelli, F. Santini, S.E. Segre, A. Tanga, A. Tuccillo, O. Tudisco, J. Wells, V. Zanza Associazione Euratom-ENEA sulla Fusione, Centro Ricerche Energia Frascati, Rome, Italy Abstract: RF power at the LH frequency (2.45 GHz) has been launched in FT. The maximum injected power was 250 kW corresponding to 6 kW/cm^2. In low-density D operation (n_bar = 4 x 10^13 cm^-3) a strong interaction with electrons causes current-drive effects and electron and ion bulk heating. At n_bar = 10^14 cm^-3, fast neutral tail in H and neutron enhancement in D have been observed. At higher densities, this ion-wave interaction tends to disappear with the onset of parametric decay instabilities. HIGH-BETA POLOIDAL PLASMAS AND CURRENT DRIVE BY ECRH ON TOSCA M.W. Alcock, B. Lloyd, A.W. Morris, D.C. Robinson, D.F.H. Start Culham Laboratory, Abingdon, Oxon., United Kingdom Abstract: High-power ECRH has been used on the TOSCA device to produce high values of beta poloidal and to investigate current drive. Plasmas with values of poloidal beta up to 2.5 have been produced by gas puffing and Ohmic heating alone. The value of poloidal beta decreases as the current increases. Experiments and theory on wave-driven currents are in reasonable agreement but give low efficiency. This current decreases as the resonance is moved to the outside of the tokamak, providing possible evidence for the reduction of the current due to trapped electrons. MEASUREMENTS OF TRANSPORT COEFFICIENTS IN THE T-10 DEVICE A.B. Berlizov, G.A. Bobrovskij, N.L. Vasin, A.N. Vertiporokh, N.D. Vinogradova, V.A. Vershkov, N.M. Gegechkori, E.P. Gorbunov, Yu.V. Esipchuk, S.L. Efremov, V.A. Zhuravlev, V.S. Zaveryaev, A.Ya. Kislov, S.Yu. Luk'yanov, Yu.S. Maksimov, G.E. Notkin, A.A. Medvedev, A.B. Pimenov, K.A. Razumova, V.A. Rantsev-Kartinov, M.M. Stepanenko, V.S. Strelkov, V.V. Timonin, V.M. Chicherov, D.A. Shcheglov, A.N. Fyakhretdinov I.V. Kurchatov Institute of Atomic Energy, Moscow, USSR Abstract: A description is given of experiments for determining the transport coefficients from measurements of the radial profiles of the plasma parameters in the T-10 in regimes with different magnetic fields B_z, different q(a_L) and different densities. It is shown that heat conductivity is determined by different mechanisms in three distinctive zones of the discharge: Zone I (sawtooth oscillation region), Zone II (main gradient region), and Zone III (periphery). ALFVEN WAVE EXPERIMENTS IN TCA A. de Chambrier, A.D. Cheetham, A. Heym, F. Hofmann, B. Joye, R. Keller, A. Lietti, J.B. Lister, A. Pochelon, W. Simm, J.L. Toninato, A. Tuszel Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne, Switzerland Abstract: The low-power experiments carried out on the TCA tokamak have shown that the antenna system excites the shear Alfvén wave as predicted by numerical codes. The existence of sets of discrete spectra corresponding to global eigenmodes of the Alfvén wave has been experimentally shown. Preliminary higher power experiments have produced increases in electron and ion temperatures accompanied by a substantial increase in the radiated power loss. Indications are that metal impurities are playing a dominant role. PLASMA HEATING AND CURRENT DRIVE BY ALFVEN WAVES R.A. Demirkhanov, A.G. Kirov, G.I. Astapenko, S.E. Il'inskij, Eh.M. Lomakin, V.V. Onishchenko, L.F. Ruchko, A.V. Sukhachev, V.D. Medun, N.I. Malykh Sukhumi Institute of Physics and Technology, Sukhumi, USSR Abstract: The results of experimental studies on plasma heating, stationary current drive and impurity transport phenomena with Alfvén waves excited in the R-O5 tokamak and the R-O stellarator are given. It has been shown experimentally that it is possible to remove the impurity ions when their cyclotron frequency is close to the Alfvén wave frequency. In the stationary stage, Alfvén heating leads to an increase in the plasma temperature, a rise in beta_J (beta_J ~ 2-3) and in the confinement time, together with an improvement in MHD stability. COMPREHENSIVE ANALYSIS OF ANTENNA-PLASMA COUPLING IN ICR HEATING OF TOKAMAKS AND STUDY OF ENERGY DEPOSITION V.P. Bhatnagar, M.P. Evrard, D.W. Faulconer, P. Geilfus, R. Koch, M. Luwel, A.M. Messiaen, D.I.C. Pearson, P.E. Vandenplas, R.R. Weynants Laboratoire de Physique des Plasmas, Ecole Royale Militaire, Brussels, Belgium Abstract: A unified account of the modelling of launching structures for heating tokamaks in the ion-cyclotron range of frequencies is given. Three mechanisms of coupling energy to the plasma are identified: (a) direct coupling, (b) coaxial modes propagating in the vacuum layer between plasma and wall, and (c) surface waves in the outer plasma gradient. Power deposition profiles are computed using a ray-tracing code taking full account of toroidal geometry. ICRF HEATING EXPERIMENT IN JFT-2 H. Kimura, H. Matsumoto, K. Odajima, S. Konoshima, T. Yamamoto, N. Suzuki, K. Hoshino, Y. Miura, T. Matsuda, H. Takeuchi, T. Sugie, S. Kasai, T. Yamauchi, H. Kawashima, T. Ogawa, T. Kawakami, T. Shoji, M. Mori, H. Ogawa, Y. Uesugi, K. Ohasa, S. Yamamoto, M. Maeno, S. Sengoku, H. Nakamura, H. Ohtsuka, T. Matoba, A. Funahashi, Y. Tanaka Japan Atomic Energy Research Institute, Tokai-mura, Japan Abstract: High-field-side excitation is investigated in detail in JFT-2. For n_H/n_D < 10%, RF power couples preferentially to ions in the plasma core. With P_net ~ 500 kW, central ion temperature increased from 0.4 keV to 0.7 keV, and electron temperature from 0.5 keV to 0.75 keV. For the mode conversion regime (n_H/n_D > 30%), RF power couples dominantly with electrons. The origin of metal impurities during heating is investigated; a strong correlation is confirmed between influx and fast ions localized in the scrape-off layer. INVESTIGATION OF ELECTRON CYCLOTRON HEATING IN THE FT-1 TOKAMAK OVER A WIDE RANGE OF PLASMA DENSITIES Yu.F. Baranov, N.E. Bogdanova, D.G. Bulyginskij, V.K. Gusev, M.M. Larionov, L.S. Levin, G.T. Razdobarin, V.I. Fedorov A.F. Ioffe Physicotechnical Institute, Leningrad, USSR Abstract: By using an extraordinary wave fed into a tokamak from the high-magnetic-field side, ECH can be performed at increased plasma densities. In FT-1 with a 60-kW, 30-GHz gyrotron, electron energy is increased by 30-35% and loop voltage is reduced. On increasing density, the heating zone is displaced towards the plasma edge. EQUILIBRIUM, STABILITY AND HEATING OF PLASMAS IN LINEAR AND TOROIDAL EXTRAP PINCHES B. Bonnevier, H.E. Dalhed, J.R. Drake, T. Hellsten, P. Karlsson, R. Landberg, B. Lehnert, J. Scheffel, M. Tendler, E. Tennfors, B. Wilner Royal Institute of Technology, Stockholm, Sweden Abstract: The Extrap scheme consists of a Z-pinch immersed in an octupole field. Globally stable Z-pinch equilibria with a distributed plasma current density and a duration of about 100 Alfvén transit times have been observed in linear and toroidal sector experiments. Finite-Larmor-radius effects and separatrix constraints provide stability. A scheme for ICRF heating in configurations with a magnetic neutral line is analysed. HIGH-BETA NEOCLASSICAL CURRENT AND STABILITY EXPERIMENTS J.D. Callen, R.N. Dexter, C.M. Fortgang, H.R. Garner, A.G. Kellman, D.W. Kerst, M.W. Phillips, S.C. Prager, J.C. Sprott, E.J. Strait, J.C. Twichell, M.C. Zarnstorff University of Wisconsin, Madison, Wisconsin, USA Abstract: Equilibrium neoclassical plasma currents and plasma stability at high values of beta have been studied in the Levitated Toroidal Octupole. The bootstrap and Pfirsch-Schlüter currents have for the first time been experimentally observed in agreement with neoclassical theory. Stable plasmas have been produced with beta values up to 11% (2.5 times the ideal MHD ballooning limit), explained by finite-ion-gyroradius effects. LOWER-HYBRID CURRENT-DRIVE EXPERIMENTS IN T-7 TOKAMAK V.V. Alikaev, V.L. Vdovin, D.P. Ivanov, N.V. Ivanov, V.I. Il'in, A.M. Kakurin, A.Ya. Kislov, P.E. Kovrov, V.A. Kochin, P.P. Khvostenko, I.N. Khromkov, V.V. Chistyakov, J. Datlov, F. Jacek, P. Klima, V. Kopecky, J. Preinhaelter, K. Jakubka I.V. Kurchatov Institute of Atomic Energy, Moscow, USSR and Institute of Plasma Physics, Prague, Czechoslovakia Abstract: Experiments on current drive by lower-hybrid waves (900 MHz, 250 kW, 50 ms) have been carried out in the T-7 tokamak. The current drive manifests itself by a drop in loop voltage and a rise in total plasma current, accompanied by suppression of X-ray ripple intensity emitted from the plasma. FUSION REACTOR PLASMAS WITH POLARIZED NUCLEI R.M. Kulsrud, H.P. Furth, E.J. Valeo, R.V. Budny, D.L. Jassby, B.J. Micklich, D.E. Post, M. Goldhaber, W. Happer Princeton University and Brookhaven National Laboratory, USA Abstract: Techniques of bulk polarization could be used to fuel a reactor with polarized hydrogenic atoms so as to form a plasma of polarized nuclei. Once polarized, nuclei can maintain their state with high probability during their lifetime in the reactor. Advantages include enhancement of D-T reaction rate by up to 50%, directional control of emission products (alpha particles and neutrons), and potential suppression of D-D reactions in a D-3He reactor. CURVATURE-DRIVEN TRAPPED-PARTICLE MODES IN TANDEM MIRRORS H.L. Berk, M.N. Rosenbluth, H.V. Wong, T.M. Antonsen Jr., D.E. Baldwin, B. Lane University of Texas at Austin, University of Maryland, LLNL, and MIT, USA Abstract: The variational structure of the plasma linear response function is used to demonstrate the relation of MHD and trapped-particle instabilities. In tandem mirrors with thermal barriers, the trapped-particle instability growth rate can approach that of MHD instabilities. Stabilizing effects due to differences in electron and ion orbits and destabilizing effects from E x B drift variation along field lines are analysed. PLASMA PROPERTIES AND ION HEATING IN EBT-S AND HOT ELECTRON RINGS AT TRW F.W. Baity et al. (ORNL), J.D. Barter et al. (TRW), F.M. Bieniosek et al. (McDonnell Douglas), R.A. Dandl et al. (AMPC), G.A. Hallock et al. (RPI), USA Abstract: EBT-S has been heated with up to 200 kW of 28-GHz microwave power. Electron temperatures of ~1 keV have been reached at densities of (0.5-2) x 10^18 m^-3. Electron confinement is approximately classical with tau_E ~ 2-5 ms. Fast-wave ICH (15-50 MHz) produced significant ion tail heating (up to 240 eV) and doubled the stored energy in relativistic electron annuli. Multiple-frequency ECRH (MFECH) on SM-1 produced 4-fold increases in ring stored energy. EXPERIMENTAL AND NUMERICAL STUDIES ON PLASMA CONFINEMENT IN NAGOYA BUMPY TORUS (NBT) M. Fujiwara, T. Kamimura, M. Hosokawa, T. Shoji, H. Iguchi, H. Sanuki, M. Tanaka, M. Aizawa, K. Takasugi, F. Tsuboi, H. Tsuchidate, K. Matsunaga, K. Kadota, A. Tsushima, K.W. Whang, H. Ikegami Institute of Plasma Physics, Nagoya University, Nagoya, Japan Abstract: Energy loss from hot electron rings is confirmed to be classical Coulomb drag. ICH up to 200 kW increased ion temperature by 300 eV and enhanced positive ambipolar potentials. Numerical studies demonstrate confinement of particles with W <= A e phi. A novel inverse-dee (ID) coil bumpy torus configuration is proposed to enhance aspect ratio and improve alpha-particle confinement. HELIOTRON STUDIES K. Uo, A. Iiyoshi, T. Obiki, O. Motojima, S. Morimoto, A. Sasaki, K. Kondo, M. Sato, T. Mutoh, H. Zushi, H. Kaneko, S. Besshou, F. Sano, T. Mizuuchi, S. Sudo, K. Hanatani, M. Nakasuga, I. Ohtake, M. Iima, Y. Nakashima, N. Nishino Plasma Physics Laboratory, Kyoto University, Kyoto, Japan Abstract: ECRH produced a currentless plasma (T_e(0)=1100 eV, T_i(0)=120 eV, n_e_bar=5x10^18 m^-3) using a 28-GHz 200-kW gyrotron. NBI heating (1.6 MW) achieved T_i(0) ~ T_e(0) ~ 660 eV with n_e_bar = 3x10^19 m^-3, central beta ~ 1%, and heating efficiency of 2 eV*P_abs(kW)/n_e(10^19 m^-3). Part II presents conceptual design studies of the Heliotron H steady-state 1200 MW(e) commercial reactor without Joule current. PLASMA HEATING AND CONFINEMENT IN THE KHAR'KOV STELLARATORS A.V. Arsen'ev et al. Institute of Physics and Technology, Ukrainian Academy of Sciences, Khar'kov, USSR Abstract: Review of experimental results on Uragan-2 (l=3 stellarator), Vint-20 (l=1 torsatron), and Uragan-3 (l=3 torsatron with divertor). RF currentless plasma production and heating by Alfvén and ion-cyclotron waves yielded n_e <= 2 x 10^13 cm^-3, T_i <= 600 eV with P <= 500 kW. In Ohmic regimes, energy confinement was governed by current-driven magnetic field fluctuations, with tau_E proportional to 1/I_p. NEUTRAL-INJECTION HEATING IN THE WENDELSTEIN VII-A STELLARATOR W VII-A Team and NI Group, Max-Planck-Institut für Plasmaphysik, Garching, FRG Abstract: A high-density deuterium plasma with beta(0) <= 1% at B_0 = 3.2 T, n_e0 > 10^14 cm^-3, T_i = 1 keV, T_e = 0.6 keV is maintained by neutral injection (27 kV, H2, P_N ~ 1 MW). Pellet injection (D2) increased target density. The currentless phase was extended to 150 ms by reducing oxygen contamination via Ti gettering. Ion thermal transport agrees with neoclassical predictions, while electron conduction follows chi_e ~ 1/(n T_e^2/3). EXPERIMENTAL INVESTIGATION OF THE SPHEROMAK CONFIGURATION M. Yamada et al. (PPPL), C. Chin-Fatt et al. (Univ. of Maryland), C.W. Barnes et al. (LANL), USA Abstract: Spheromak characteristics have been investigated using three formation schemes: magnetized coaxial gun (CTX), field-reversed theta-pinch with z-discharge (PS-1,2), and electrodeless quasi-static flux core (Proto S-1). Parameters achieved: B_t ~ B_p <= 5 kG, T_e <= 50 eV, n_e = (0.3-10) x 10^14 cm^-3, lifetimes up to 1 ms. Passive Figure-8 stabilization coils and center conductors successfully stabilized the destructive n=1 tilt and shift MHD modes. EXPERIMENTAL STUDIES OF FIELD-REVERSED CONFIGURATION CONFINEMENT IN FRX-C R.E. Siemon et al., Los Alamos National Laboratory, USA Abstract: In the large-bore (0.5 m dia.) FRX-C FRC experiment at 20 mtorr fill pressure, particle confinement time was measured as tau_N ~ 140 micros, confirming the scaling tau_N proportional to R^2 compared with FRX-B (tau_N ~ 39 micros). Parameters: n_bar ~ 4 x 10^15 cm^-3, T_e ~ 100 eV, T_i ~ 150 eV, R/rho_i ~ 30. At 5 mtorr, hotter neutron-producing plasmas were obtained: n_bar ~ 2 x 10^15 cm^-3, T_e ~ 170 eV, T_i ~ 600 eV. COMPACT TOROIDAL PLASMAS: SIMULATIONS AND THEORY D.S. Harned et al. (LANL), D.V. Anderson et al. (NMFECC/LLNL), S.P. Auerbach et al. (LLNL), A. Aydemir et al. (IFS Austin), C. Bernard (GA), W.M. Tang (PPPL), C. Seyler (Cornell), J. Tataronis (Univ. Wisconsin), USA Abstract: Realistic FRC equilibria and stability to n=1 tilt modes are analysed; FLR effects are shown to provide stability for rho_i ~ r_sep/10. 2-D hybrid simulations show particle loss on open field lines causes rotation driving the n=2 rotational instability. Power balance models show impurity radiation dominates present gun-generated CT plasmas. Taylor relaxation allows steady-state current drive. EXPERIMENTAL STUDIES ON CONFINEMENT OF FIELD-REVERSED-CONFIGURATION PLASMA T. Minato et al. (Osaka Univ.), Y. Nogi et al. (Nihon Univ.), Y. Aso et al. (Nagoya Univ.), Japan Abstract: Compact toroids in PIACE-I/II, NUCTE-I/II and STP-L have lifetimes of 15 to 70 micros limited by n=2 rotational instability. An empirical scaling tau_s proportional to n_bar_e * r_s * l_p * L_c was found. Guiding magnetic fields delayed end-shorting and extended the stable period. Quadrupole fields of ~0.06-0.1 T completely suppressed the n=2 rotational instability in PIACE-II. MERGING EXPERIMENT AND SIMULATION OF COMPACT TOROIDS K. Watanabe et al. (Osaka Univ.), T. Sato et al. (Hiroshima Univ.), Japan Abstract: In CTCC-1, successive injection of two spheromaks into a copper flux conserver demonstrated stable merging; total toroidal flux was additive (Psi_T = Psi_T1 + Psi_T2) while poloidal flux matched the maximum of the two. 2-D MHD simulations showed total magnetic helicity is conserved while magnetic energy decreases during merging. 3-D simulations demonstrated the 3-D reconnection mechanism during spheromak tilt disruption. HIGH-BETA TOKAMAK PLASMA PHYSICS STUDIES C.K. Chu, A.V. Deniz, D.J. Elkin, G. Erlebacher, R.A. Gross, R. Izzo, S. Johnston, C. Kostek, F. Levinton, M. Machida, T.C. Marshall, R.L. Merlino, G.A. Navratil, D. Oepts Columbia University, New York, N.Y., USA Abstract: Research on Torus II high-beta tokamak (b/a=2, R_0=0.225 m, a=0.065 m) demonstrated central beta_0 ~ 42%, <beta> ~ 13%, n_e(0) ~ 2 x 10^21 m^-3, T_e ~ 80 eV. A toroidal diamagnetic well and 40% outward shift in the pressure peak confirmed epsilon*beta_p > 1. Growing density fluctuations characteristic of low-n MHD ballooning modes were observed on the outer edge. BETA INCREASE IN A BELT-PINCH PLASMA BY FAST MAGNETOSONIC WAVE HEATING V. Erckmann, A. Mayer, G. Müller, K. Schwörer, M. Thumm, R. Wilhelm Institut für Plasmaforschung, Universität Stuttgart, FRG Abstract: Fast magnetosonic wave absorption at omega = 2*omega_ci (1.2 MHz, 5 micros, k_perp*r_ci ~ 1) was investigated in the belt-pinch HECTOR. When the resonance layer is at the magnetic axis, beta increased from 30% to 70% and T_i(0) reached 250 eV at P_in ~ 200 MW. The plasma passed through a sequence of flux-conserving tokamak (FCT) equilibria with <beta> up to 46% (beta_p = 4.0). SUPPRESSION OF LOSSES IN A COMPACT TORUS WITH PROGRAMMED SHAPING OF THE MAGNETIC STRUCTURE V.V. Belikov, V.M. Goloviznin, V.K. Korshunov, A.P. Kreshchuk, R.Kh. Kurtmullaev, Ya.N. Laukhin, A.I. Malyutin, A.P. Proshletsov, O.L. Rostovtsev, V.N. Semenov, V.F. Strizhov I.V. Kurchatov Institute of Atomic Energy, Moscow, USSR Abstract: Experiments on the TOR and BN facilities (B ~ 7-11 kG, n ~ (1-3) x 10^15 cm^-3) demonstrate that programmed magnetic control and delayed longitudinal shock wave compression suppress magnetic flux and energy losses. Ion temperatures of T_i ~ 1.4 keV with collisionless heating (lambda_ii/L ~ 50) were achieved. INERTIAL FUSION RESEARCH BASED ON PULSED POWER G. Yonas, Sandia National Laboratories, Albuquerque, New Mexico, USA Abstract: PBFA II (3.5 MJ, 100 TW) is being designed for inertial fusion ignition using imploding foils or light ion beams to deliver 100 TW/cm^2 and 1 MJ to a target. Proto II imploding foil data demonstrate efficient conversion to foil kinetic energy (60 kJ at 5 MA, 10 ns stagnation). Proton diodes on Proto I have delivered ~2 TW/cm^2 with 20 mrad divergence. Heavier ions such as C+2 or Li+1 at >10 MV are projected to achieve required focal brightness. LIGHT-ION INERTIAL CONFINEMENT FUSION RESEARCH AT NAVAL RESEARCH LABORATORY G. Cooperstein, R.J. Barker, D.G. Colombant, A. Drobot, Shyke A. Goldstein, R.A. Meger, D. Mosher, P.F. Ottinger, F.L. Sandel, S.J. Stephanakis, F.C. Young Naval Research Laboratory, Washington, D.C., USA Abstract: High-brightness proton beams (0.4 MA, 1 MV) with source power brightness > 10 TW/(cm^2*rad^2) were extracted from 20 cm^2 pinch-reflex diodes on Gamble II. An equatorial PRD demonstrated 50% proton efficiency. Stopping power of MeV deuterons in heated plasmas showed ~40% enhancement over cold targets at 0.25 MA/cm^2. Ion beam transport in z-discharge channels and final magnetic focusing were demonstrated. RESEARCH PROGRESS IN INTENSE ION BEAM PRODUCTION FOR INERTIAL CONFINEMENT FUSION AT CORNELL UNIVERSITY H. Bluhm, J.B. Greenly, D.A. Hammer, B.R. Kusse, J. Maenchen, A. Mankofsky, J. Neri, R. Pal, T.J. Renk, G.D. Rondeau, R.N. Sudan Laboratory of Plasma Studies, Cornell University, Ithaca, New York, USA Abstract: Studies of magnetically insulated ion diodes (MIDs) with flashboard anodes showed ion beam divergence as small as 0.5 degrees at >10^8 W/cm^2. On the LION accelerator (10^12 W, 1.8 MV), >10^9 W/cm^2 beams were generated. Pure heavy ion beams (Ba+, Ba++, Na+) were produced using hydrocarbon-free flashboards. 2.5-D hybrid simulations showed 93% beam energy transport in 1 m z-pinch plasma channels. LIGHT ION BEAM FUSION RESEARCH IN JAPAN K. Imasaki et al. (ILE Osaka Univ.), K. Yatsui et al. (Tech. Univ. of Nagaoka), Japan Abstract: On REIDEN IV (modified to 3 MV), pinch reflex diode experiments yielded 0.2 TW ion beams. Beam transport in a CO2 laser guided plasma channel achieved 150 keV energy loss over 40 cm. Ablation pressure scaled as P_a = 3 x 10^-3 I^0.7 bar (I in W/cm^2). At Nagaoka, geometric focusing of proton beams in MIDs on ETIGO-I gave focal spot radius r* ~ 16 mm with 6 degrees total divergence, and transport efficiency >85% in wall-stabilized plasma channels. STATUS OF RELATIVISTIC-ELECTRON-BEAM-GENERATOR-DRIVEN INERTIAL-CONFINEMENT FUSION L.E. Aranchuk et al., I.V. Kurchatov Institute of Atomic Energy, Moscow, USSR Abstract: Progress on the Angara ICF programme is reviewed. Focusing in diodes on Angara-I and Mirage reached instantaneous current densities up to 80 MA/cm^2 (6 x 10^13 W/cm^2). Enhanced electron energy deposition in thin foils by factors of 8-10 due to magnetic stopping was confirmed. Electrodynamic liner acceleration with currents up to 1.5 MA produced imploding plasma shells. INVESTIGATION OF THE NEUTRON PRODUCTION PHASES OF A LARGE PLASMA FOCUS DEVICE H. Herold et al. (IPF Stuttgart), A. Hayd et al. (MAN München), FRG Abstract: Theoretical and experimental studies of the Poseidon plasma focus (280 kJ, 60 kV, I_pinch <= 1.1 MA) using a REDUCE-based non-linear hybrid code showed that for I_pinch > 500 kA, strong neutron emission occurs in the intermediate phase prior to m=0 onset due to current filamentation and high electric fields (300 kV/cm). Post-m=0 emission is governed by long-lived turbulence soliton packets (135 ns lifetime). EXPERIMENTAL PROGRESS IN PLASMA DYNAMICS AND GENERATION OF ENERGETIC PARTICLES IN DENSE PLASMA FOCUS M. Yokoyama et al. (ILE Osaka Univ.), K. Hirano et al. (Gunma Univ.), Japan Abstract: In Mather-type device A (30 kV, 18 kJ), deuteron beams up to >3 MeV and ion temperatures up to 11 keV were observed using D-D/D-3He reaction ratios and activation analysis. In device B, streak interferometry and Thomson analysis confirmed a 'moving plasma diode mechanism' for neutron generation. In Filippov device C, maximum collapse occurred at the collision of the current sheet with the reflected shock wave. TASKA - A TANDEM MIRROR FUSION ENGINEERING TEST FACILITY TASKA-Team (P. Komarek, Compiler), Kernforschungszentrum Karlsruhe GmbH (FRG) & Univ. of Wisconsin (USA) Abstract: TASKA is a DT fusion engineering test facility (86 MW fusion power, Q=0.74, wall loading 1.5 MW/m^2) based on the tandem mirror principle with inboard thermal barriers. A 20 T barrier field is provided by a hybrid superconducting (14 T) and normal-conducting insert (6 T) coil. Auxiliary heating comprises 40 MW ICRF, 15 MW ECRH, and 62 MW NBI. The central cell length is 19.2 m. The tritium breeding ratio is 1.0 using Pb83Li17, and blanket/material test modules are provided. KARIN-I: CONCEPTUAL DESIGN OF A MOVING-RING REACTOR KARIN-I Working Group, Institute of Plasma Physics, Nagoya University, Japan Abstract: Conceptual design of a 500 MW(e) commercial D-T reactor containing ten moving plasma rings produced by REB injection (25 MeV, 1.7 MA), heated by major radius compression, and conveyed through a 50 m linear burning section with an annular flowing liquid lithium blanket outside a SiC first wall. Liquid lithium acts as coolant, breeder, and tilt stabilizer. Magnetic expansion recovers energy from spent rings with 70% efficiency. CONCEPTUAL DESIGN OF A MOVING-RING REACTOR A.C. Smith Jr. et al. (PG&E, LLNL, Cornell, GA, NYU, UNM, Univ. of Michigan), USA Abstract: Design of a 99 MW(e) net prototype Moving-Ring Reactor using field-reversed compact toroids. Rings formed by a coaxial gun undergo adiabatic magnetic compression to ignition (75 keV), shuttle sequentially through three burn stations, and are refuelled by D-T-3He pellets. Helium-cooled SiC and Li2O blanket minimizes induced radioactivity and permits hands-on maintenance outside the blanket. DEVELOPMENT OF HYDROGEN PELLET INJECTORS AND PELLET FUELLING EXPERIMENTS AT OAK RIDGE NATIONAL LABORATORY S.L. Milora, S.K. Combs, C.A. Foster, W.A. Houlberg, J.T. Hogan, D.D. Schuresko, S.E. Attenberger (ORNL), G.L. Schmidt (PPPL), M.J. Greenwald, S. Wolfe, J. Parker (MIT), USA Abstract: Progress on pneumatic and centrifugal mechanical hydrogen/deuterium pellet injectors. The Advanced Mechanical Injector (AMI) achieved 1 km/s pellet speeds at 40 s^-1. Pneumatic guns achieved 1200 m/s with 1.6 mm pellets. Four-pellet pneumatic injectors were operated on PDX, showing stable plasma recovery and density increases up to 50% with deeper penetration for successive pellets. BLANKET AND SHIELD EXPERIMENTS IN FUSION NEUTRONICS SOURCE (FNS) T. Nakamura, H. Maekawa, Japan Atomic Energy Research Institute, Tokai-mura, Japan Abstract: Experiments using the intense FNS 14-MeV D-T neutron facility include: (1) tritium production rate distribution in a pseudo-spherical Li2O-C assembly measured by Li2CO3 pellets and LiF TLD self-irradiation; (2) TOF angular leakage spectra from Li2O slab assemblies; and (3) duct streaming experiments in an L-shaped concrete access maze with fast-neutron and gamma-ray dose/spectrum measurements. FEEDBACK CONTROL OF THERMAL INSTABILITY BY COMPRESSION AND DECOMPRESSION M. Okamoto, M. Ohnishi, K. Hirano, T. Amano, IPP Nagoya University and Kyoto University, Japan Abstract: Active feedback control of fusion output power by plasma compression-decompression via vertical field regulation is modelled for an ignition tokamak. Zero-dimensional and 1-D transport simulations show thermal runaway can be suppressed completely with small major radius variations (Delta R/R <= 0.11% with 15% measurement error), enabling steady-state burning and load-following operation. SELECTED POSTER PAPERS (Session V): - V-1: M. Cotsaftis on low-m magnetic mode activity and disruption control in tokamaks by slow current profile control. - V-2: E. Canobbio and R. Croci on analytical solution of the QLFP equation for RF current drive by LH waves in Lorentz electron gas. - V-3: D. Correa-Restrepo on resistive ballooning modes in 3-D MHD configurations and derivation of tearing-mode-like dispersion relation. - V-4: M.G. Haines and F. Marsh on electrothermal instability leading to fine-scale filamentary structures and direct ion heating in tokamaks. - V-5: V.D. Pustovitov et al. on generalized 2-D equilibrium and stability in l=2 and l=3 stellarators (W-VIIA, L-2, Heliotron-E, ATF, U-3), showing beta limits of 10-12%. - V-6: K. Okano et al. on current generation by anisotropic interaction of fusion alpha particles with ICRF waves. - V-7: A.B. Mikhajlovskij et al. on ballooning MHD modes in toroidal traps with spatial magnetic axes. - V-8: A.G. Dikij et al. on anomalous absorption of large-amplitude Alfvén/ICRF waves in Uragan-2. - V-9: J.M. Dawson et al. on theory and particle simulation of ICRH, ECRH mode conversion, LH current drive, and gyrotron modelling. - V-10: G. Anania et al. on stellarator expansion, superbanana transport, and 3-D torsatron stability. - V-11: C.L. Hedrick et al. on neoclassical transport, ambipolar potential, and ECH/ICRH theory in EBT.