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We introduce a topology optimization method to design permanent magnets for advanced stellarators. Recent research shows that permanent magnets have great potential to simplify stellarator coils. We adopt state-of-the-art numerical techniques to determine the presence of magnets in the entire design space. The FAMUS code is developed and it can design engineering-feasible permanent magnets for general stellarators satisfying the constraints of the maximum material magnetization and explicit forbidden regions. FAMUS has been successfully verified against the previously proposed linear method. Three different permanent magnet designs together with planar TF coils for a half-Tesla NCSX configuration have been obtained for demonstrations. The designs have good accuracy in generating the desired equilibrium and offer considerably large plasma access on the outboard side. The results show that FAMUS is a flexible, advanced numerical tool for future permanent magnet stellarator designs.

The mission of the National Spherical Torus Experiment (NSTX) is the demonstration of the physics basis required to extrapolate to the next steps for the spherical torus (ST), such as a plasma facing component test facility (NHTX) or an ST based component test facility (ST-CTF), and to support ITER. Key issues for the ST are transport, and steady state high β operation. To better understand electron transport, a new high-k scattering diagnostic was used extensively to investigate electron gyro-scale fluctuations with varying electron temperature gradient scale length. Results from n = 3 braking studies are consistent with the flow shear dependence of ion transport. New results from electron Bernstein wave emission measurements from plasmas with lithium wall coating applied indicate transmission efficiencies near 70% in H-mode as a result of reduced collisionality. Improved coupling of high harmonic fast-waves has been achieved by reducing the edge density relative to the critical density for surface wave coupling. In order to achieve high bootstrap current fraction, future ST designs envision running at very high elongation. Plasmas have been maintained on NSTX at very low internal inductance l i ∼ 0.4 with strong shaping (κ ∼ 2.7, δ ∼ 0.8) with β N approaching the with-wall β-limit for several energy confinement times. By operating at lower collisionality in this regime, NSTX has achieved record non-inductive current drive fraction f NI ∼ 71%. Instabilities driven by super-Alfvénic ions will be an important issue for all burning plasmas, including ITER. Fast ions from NBI on NSTX are super-Alfvénic. Linear toroidal Alfvén eigenmode thresholds and appreciable fast ion loss during multi-mode bursts are measured and these results are compared with theory. The impact of n > 1 error fields on stability is an important result for ITER. Resistive wall mode/resonant field amplification feedback combined with n = 3 error field control was used on NSTX to maintain plasma rotation with β above the no-wall limit. Other highlights are results of lithium coating experiments, momentum confinement studies, scrape-off layer width scaling, demonstration of divertor heat load mitigation in strongly shaped plasmas and coupling of coaxial helicity injection plasmas to ohmic heating ramp-up. These results advance the ST towards next step fusion energy devices such as NHTX and ST-CTF.

Aliasing artifacts are eliminated from computer generated images of textured polygons by equivalently filtering both the texture and the edges of the polygons. Different filters can be easily compared because the weighting functions that define the shape of the filters are pre-computed and stored in lookup tables. A polygon subdivision algorithm removes the hidden surfaces so that the polygons are rendered sequentially to minimize accessing the texture definition files. An implementation of the texture rendering procedure is described.

Aliasing artifacts are eliminated from computer generated images of textured polygons by equivalently filtering both the texture and the edges of the polygons. Different filters can be easily compared because the weighting functions that define the shape of the filters are pre-computed and stored in lookup tables.A polygon subdivision algorithm removes the hidden surfaces so that the polygons are rendered sequentially to minimize accessing the texture definition files. An implementation of the texture rendering procedure is described. COMPUTING REVIEWS CATEGORY:8.2

Situational awareness applications require a highly detailed geospatial visualization covering a large geographic area. Conventional polygon based terrain modeling would exceed the capacity of current computer rendering. Terrain visualization techniques for a situational awareness application are described in this case study. Visualizing large amounts of terrain data has been achieved using very large texture maps. Sun shading is applied to the terrain texture map to enhance perception of relief features. Perception of submarine positions has been enhanced using a translucent, textured water surface. Each visualization technique is illustrated in the accompanying video tape. Keywords: Terrain Visualization, Situational Awareness, DTED, Digital Maps lntroducti,onSituational awareness visualization applications require the representation of large geographic areas and thousands of military units. The extent of the area of interest (playbox) is typically one million square miles. Observers want to see the highest resolution data available and be able to navigate through the model at interactive rates. The geo-spatial information &splayed consists of elevation data, a variety of maps, and high resolution imagery. The size of the playbox and the amount of data present a considerable demand on both the terrain model and the visualization software. A Joint Forces operation simultaneously involves ground, sea, and air forces. Military units must be displayed in the context of terrain, on the sea, under the sea, and in the air. Collateral maps and images also aid in understanding the movement and placement of units.The Joint Operations Visualization Environment (JOVE) [5] has been developed to assist top level military decision makers. JOVE uses three rear projected displays driven from an SGI Onyx2 Infinite Reality (IR) computer. Interaction is provided through a joystick and speech interface. JOVE also allows accurate navigation through the model over a range of viewer positions. A typical scene from the situational awareness application is shown in Video Sequence 1. This case study describes techniques used for realistic modeling and navigation of geo-spatial data in JOVE. Section 2 presents an outline of our model and its components. Section 3 describes visualization of elevation data. Section 4 describes techniques to improve perception of sea and under sea vessels. Section 5 discusses the visualization of maps and overhead imagery. The Earth ModelOur model starts with a sphere representing the Earth. The entire world is portrayed because:1. Units can move out of the playbox.2. Far-ranging units, such as aircraft, could be stationed anywhere around the world. Satellite imagery [I] of the Earth is texture-mapped onto the geometric model. The cloudless imagery portrays the world at 4 kilometer resolution. Lines of latitude and longitude are drawn over the imagery at 10 degree intervals. The sphere geometry is modeled to use polygons efficiently and also to avoid thin triangles near the poles. The highest polyg...

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Abstract. The goal of the high harmonic fast wave (HHFW) research on NSTX is to maximize the coupling of RF power to the core of the plasma by minimizing the coupling of RF power to edge loss processes. HHFW core plasma heating efficiency in helium and deuterium L-mode discharges is found to improve markedly on NSTX when the density 2 cm in front of the antenna is reduced below that for the onset of perpendicular wave propagation (n onset ∝ B*k || 2 /ω). In NSTX, the observed RF power losses in the plasma edge are driven in the vicinity of the antenna as opposed to resulting from multi-pass edge damping. PDI surface losses through ion-electron collisions are estimated to be significant. Recent spectroscopic measurements suggest that additional PDI losses could be caused by the loss of energetic edge ions on direct loss orbits and perhaps result in the observed clamping of the edge rotation. Initial deuterium H-mode heating studies reveal that core heating is degraded at lower k φ (-8 m -1 relative to 13 m -1 ) as for the Lmode case at elevated edge density. Fast visible camera images clearly indicate that a major edge loss process is occurring from the plasma scrape off layer (SOL) in the vicinity of the antenna and along the magnetic field lines to the lower outer divertor plate. Large type I ELMs, which are observed at both k φ values, appear after antenna arcs caused by precursor blobs, low level ELMs, or dust. For large ELMs without arcs, the source reflection coefficients rise on a 0.1 ms time scale, which indicates that the time derivative of the reflection coefficient can be used to discriminate between arcs and ELMs.