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Design Analysis and Manufacturing Studies for ITER In-Vessel Coils

ITER is incorporating two types of In Vessel Coils (IVCs): ELM Coils to mitigate Edge Localized Modes and VS Coils to provide Vertical Stabilization of the plasma. Strong coupling with the plasma is required so that the ELM and VS Coils can meet their performance requirements. Accordingly, the IVCs are in close proximity to the plasma, mounted just behind the Blanket Shield Modules. This location results in a radiation and temperature environment that is severe necessitating new solutions for m… more

Date: July 1, 2014

Creator: Kalish, M.; Heitzenroeder, P.; Neumeyer, C.; Titus, P.; Zhai, Y.; Zatz, I. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Self-organisation Processes In The Carbon ARC For Nanosynthis

The atmospheric pressure carbon arc in inert gases such as helium is an important method for the production of nanomaterials. It has recently been shown that the formation of the carbon deposit on the cathode from gaseous carbon plays a crucial role in the operation of the arc, reaching the high temperatures necessary for thermionic emission to take place even with low melting point cathodes. Based on observed ablation and deposition rates, we explore the implications of deposit formation on th… more

Date: February 2, 2014

Creator: Ng, J. & Raitses, Yefgeny

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Ultra-High Intensity Magnetic Field Generation in Dense Plasma

I. Grant Objective The main objective of this grant proposal was to explore the efficient generation of intense currents. Whereasthefficient generation of electric current in low-‐energy-‐ density plasma has occupied the attention of the magnetic fusion community for several decades, scant attention has been paid to carrying over to high-‐energy-‐ density plasma the ideas for steady-‐state current drive developed for low-‐energy-‐ density plasma, or, for that matter, to inventing new met… more

Date: January 8, 2014

Creator: Fisch, Nathaniel J

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Systematic Effects in Type-1a Supernovae Surveys from Host Galaxy Spectra

The physical relation between the properties of Type Ia supernovae and their host galaxies is investigated. Such supernovae are used to constrain the properties of dark energy, making it crucial to understand their physical properties and to check for systematic effects relating to the stellar populations of the progenitor stars from which these supernovae arose. This grant found strong evidence for two distinct populations of supernovae, and correlations between the progenitor stellar populati… more

Date: August 23, 2013

Creator: Strauss, Michael A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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The Hamiltonian Mechanics of Stochastic Acceleration

We show how to nd the physical Langevin equation describing the trajectories of particles un- dergoing collisionless stochastic acceleration. These stochastic di erential equations retain not only one-, but two-particle statistics, and inherit the Hamiltonian nature of the underlying microscopic equations. This opens the door to using stochastic variational integrators to perform simulations of stochastic interactions such as Fermi acceleration. We illustrate the theory by applying it to two ex… more

Date: July 17, 2013

Creator: Burby, J. W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Progress in Simulating Turbulent Electron Thermal Transport in NSTX

Nonlinear simulations based on multiple NSTX discharge scenarios have progressed to help differentiate unique instability mechanisms and to validate with experimental turbulence and transport data. First nonlinear gyrokinetic simulations of microtearing (MT) turbulence in a high-beta NSTX H-mode discharge predict experimental levels of electron thermal transport that are dominated by magnetic flutter and increase with collisionality, roughly consistent with energy confinement times in dimension… more

Date: July 17, 2013

Creator: Guttenfelder, Walter; Kaye, S. M.; Ren, Y.; Bell, R. E.; Hammett, G. W.; LeBlanc, B. P. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Performance Evaluation of K-DEMO Cable-in-conduit Conductors Using the Florida Electro-Mechanical Cable Model

The United States ITER Project Office (USIPO) is responsible for design of the Toroidal Field (TF) insert coil, which will allow validation of the performance of significant lengths of the conductors to be used in the full scale TF coils in relevant conditions of field, current density and mechanical strain. The Japan Atomic Energy Agency (JAEA) will build the TF insert which will be tested at the Central Solenoid Model Coil (CSMC) Test facility at JAEA, Naka, Japan. Three dimensional mathemati… more

Date: July 16, 2013

Creator: Zhai, Yuhu

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Simulation of Non-resonant Internal Kink Mode with Toroidal Rotation in NSTX

Plasmas in spherical and conventional tokamaks, with weakly reversed shear q pro le and minimum q above but close to unity, are susceptible to an non-resonant (m, n ) = (1, 1) internal kink mode. This mode can saturate and persist and can induce a (2; 1) seed island for Neoclassical Tearing Mode (NTMs)1 . The mode can also lead to large energetic particle transport and signi cant broadening of beam-driven current. Motivated by these important e ects, we have carried out extensive nonlinear simu… more

Date: July 16, 2013

Creator: Fu, Guoyong

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Axisymmetric Simulations of the ITER Vertical Stability Coil

The ITER in-vessel coil system includes Vertical Stability (VS) coils and Edge Localized Mode (ELM) coils. There are two large VS ring coils, one upper and one lower. Each has four turns which are independently connected. The VS coils are needed for successful operation of ITER for most all of its operating modes. The VS coils must be highly reliable and fault tolerant. The operating environment includes normal and disruption Lorentz forces. To parametrically address all these design conditions… more

Date: July 9, 2013

Creator: Titus, Peter H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Comparison of Measurement And Modeling Of Current Profile Changes Due To Neutral Bean Ion Redistribution During TAE Avalanches in NSTX

Brief "avalanches" of toroidal Alfven eigenmodes (TAEs) are observed in NSTX plasmas with several different n numbers simultaneously present. These affect the neutral beam ion distribution as evidenced by a concurrent drop in the neutron rate and, sometimes, beam ion loss. Guiding center orbit modeling has shown that the modes can transiently render portions of the beam ion phase space stochastic. The resulting redistribution of beam ions can also create a broader beam-driven current … more

Date: July 9, 2013

Creator: Darrow, Douglas

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Development of a Process to Build Polyimide Insulated Magnets For Operation at 350C

An extensive R&D program has been conducted that has confirmed the feasibility of designing and fabricating copper alloy magnets that can successfully operate at temperatures as high as 350C. The process, originally developed for the possibility of manufacturing in-vessel resonant magnetic field perturbation (RMP) coils for JET, has been optimized for insulated magnet (and, potentially, other high temperature component) applications. One of the benefits of high temperature operation is that… more

Date: July 9, 2013

Creator: Zatz, Irving J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Physics Design of a 28 GHz Electron Heating System for the National Spherical Torus Experiment Upgrade

A megawatt-level, 28 GHz electron heating system is being designed to support non-inductive (NI) plasma current (I{sub p}) start-up and local heating and current drive (CD) in H-mode discharges in the National Spherical Torus Experiment Upgrade (NSTX-U). The development of fully NI I{sub p} start-up and ramp-up is an important goal of the NSTX-U research program. 28 GHz electron cyclotron (EC) heating is predicted to rapidly increase the central electron temperature (T{sub e}(0)) of low density… more

Date: July 9, 2013

Creator: Taylor, G.; Bertelli, N.; Ellis, R. A.; Gerhardt, S. P.; Harvey, R. W.; Hosea, J. C. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Upward-facing Lithium Flash Evaporator for NSTX-U

NSTX plasma performance has been significantly enhanced by lithium conditioning [1]. To date, the lower divertor and passive plates have been conditioned by downward facing lithium evaporators (LITER) as appropriate for lower null plasmas. The higher power operation expected from NSTX-U requires double null plasma operation in order to distribute the heat flux between the upper and lower divertors making it desirable to coat the upper divertor region with Li as well. An upward aiming LITER (U-L… more

Date: July 9, 2013

Creator: Roquemore, A. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Novel Use of Water Soluble "Aquapour" As A Temporary Spacer During Coil Winding For The NSTX-U Centerstack

A major facility upgrade to the National Spherical Torus eXperiment (NSTX-U) is currently underway at Princeton Plasma Physics Laboratory (PPPL). A key component of NSTX-U is the fabrication of a new, higher field centerstack (CS). In order to simultaneously provide robust joints between the inner and outer legs of the Toroidal Field Coils (TF) and minimize radial build, the NSTX-U CS design requires that the Ohmic Heating solenoid (OH) be wound directly on the inner TF bundle. To protect the O… more

Date: July 1, 2013

Creator: Mardenfeld, Michael

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Hardwired Control Changes For NSTX DC Power Feeds

The National Spherical Torus Experiment (NSTX) has been designed and installed in the existing facilities at Princeton Plasma Physics Laboratory (PPPL). Most of the hardware, plant facilities, auxiliary sub-systems, and power systems originally used for the Tokamak Fusion Test Reactor (TFTR) have been used with suitable modifications to reflect NSTX needs. The original TFTR Hardwired Control System (HCS) with electromechanical relays was used for NSTX DC Power loop control and protection during… more

Date: June 28, 2013

Creator: Ramakrishnan, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Power Supply Changes for NSTX Resistive Wall Mode Coils

The National Spherical Torus Experiment (NSTX) has been designed and installed in the existing facilities at Princeton Plasma Physics Laboratory (PPPL). Most of the hardware, plant facilities, auxiliary sub-systems, and power systems originally used for the Tokamak Fusion Test Reactor (TFTR) have been used with suitable modifications to reflect NSTX needs. Prior to 2004, the NSTX power system was feeding twelve (12) circuits in the machine. In 2004 the Resistive Wall Mode (RWM) Coils were insta… more

Date: June 28, 2013

Creator: Ramakrishnan, S S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Progress in Developing the K-DEMO Device Configuration

K-DEMO is being studied by South Korean researchers as a follow-on to ITER and the next step toward the construction of a commercial fusion power plant. The K-DEMO mission defines a staged approach targeting operation with an initial testing phase for plasma facing components and critical operating systems to be followed by a second phase which centers on upgrading the in-vessel components for operation at 200 to 600 MWe with a planned 70% availability.

Date: June 27, 2013

Creator: Brown, Tom

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Progress in Developing the STFNSF Configuration

The design features developed for the Spherical Tokamak (ST) in the PPPL pilot plant study was used as the starting point in developing designs to meet the mission of a Fusion Nuclear Science Facility (FNSF) considering a range of machine sizes based on the influence of tritium consumption and maintenance strategies. The compact nature of a steady state operated ST device for this mission pushes operating conditions and places challenges in the design of components, device maintenance and the i… more

Date: June 25, 2013

Creator: Brown, Thomas

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Fast-wave Power Flow Along SOL Field Lines In NSTX nd The Associated Power Deposition Profile Across The SOL In Front Of The Antenna

Fast-wave heating and current drive efficiencies can be reduced by a number of processes in the vicinity of the antenna and in the scrape off layer (SOL). On NSTX from around 25% to more than 60% of the high-harmonic fast-wave power can be lost to the SOL regions, and a large part of this lost power flows along SOL magnetic field lines and is deposited in bright spirals on the divertor floor and ceiling. We show that field-line mapping matches the location of heat deposition on the lower divert… more

Date: June 21, 2013

Creator: Perkins, Roy

Item Type: Report

Partner: UNT Libraries Government Documents Department

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TRANSP Tests Of TGLF and Predictions For ITER

Gyro kinetic simulations of turbulence capture some of the features observed in transport, fluctuations, and correlations measured in tokamak plasmas. These codes calculations are CPU intensive, and are not practical for incorporation in present time-dependant transport codes, so reduced models based on these gyro kinetic codes are being used. An example is the TGLF model [1] which is a quasilinear gyrofluid model calibrated to nonlinear results from the GYRO code [2]. Recently TGLF has been in… more

Date: June 2, 2013

Creator: Robert V Budny, et al

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Collisionality Scaling of Main-ion Toroidal and Poloidal Rotation in Low Torque DIII-D Plasmas

In tokamak plasmas with low levels of toroidal rotation, the radial electric fi eld Er is a combination of pressure gradient and toroidal and poloidal rotation components, all having similar magnitudes. In order to assess the validity of neoclassical poloidal rotation theory for determining the poloidal rotation contribution to Er , Dα emission from neutral beam heated tokamak discharges in DIII-D [J.L. Luxon, Nucl. Fusion 42 , 614 (2002)] has been evaluated in a sequence of low torque (electro… more

Date: May 10, 2013

Creator: Grierson, B. A.; Burrell, K. H.; Solomon, W. M.; Budny, R. V. & Candy, J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Alcator C-Mod Experiments in Support of the ITER Baseline 15 MA Scenario

Experiments on Alcator C-Mod have addressed several issues for the ITER 15 MA baseline scenario from 2009-2012. Rampup studies show ICRF can save significant V-s, and that an H-mode in the ramp can be utilized to save 50% more. ICRF modifications to li(1) are minimal, although the Te profile is peaked relative to ohmic in the plasma center, and alter sawtooth onset times. Rampdown studies show H-modes can be routinely sustained, avoiding an OH coil over-current associated with the H-L transitio… more

Date: May 7, 2013

Creator: Kessel, C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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STELLOPT Modeling of the 3D Diagnostic Response in ITER

The ITER three dimensional diagnostic response to an n=3 resonant magnetic perturbation is modeled using the STELLOPT code. The in-vessel coils apply a resonant magnetic perturbation (RMP) fi eld which generates a 4 cm edge displacement from axisymmetry as modeled by the VMEC 3D equilibrium code. Forward modeling of flux loop and magnetic probe response with the DIAGNO code indicates up to 20 % changes in measured plasma signals. Simulated LIDAR measurements of electron temperature indicate 2 c… more

Date: May 7, 2013

Creator: Lazerson, Samuel A

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Three-dimensional, Impulsive Magnetic Reconnection in a Laboratory Plasma

Impulsive, local, 3-D reconnection is identified for the first time in a laboratory current sheet. The events observed in the Magnetic Reconnection Experiment (MRX) are characterized by large local gradients in the third direction and cannot be explained by 2-D models. Detailed measurements show that the ejection of flux rope structures from the current sheet plays a key role in these events. By contrast, even though electromagnetic fluctuations in the lower hybrid frequency range are also obse… more

Date: May 3, 2013

Creator: S Dorfman, et al

Item Type: Report

Partner: UNT Libraries Government Documents Department