05.12.2012 Views

NASA Scientific and Technical Aerospace Reports

NASA Scientific and Technical Aerospace Reports

NASA Scientific and Technical Aerospace Reports

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

<strong>and</strong> formed into a conical shape by passing through a diffractive diffuser; the resultant light is then converged by a series of<br />

lenses. Since this configuration produces light containing polarization components in all directions, the dye is excited<br />

uniformly, as discussed above.<br />

Derived from text<br />

Fluorescence; Microscopy; Optics; Illumination<br />

20060002428 Jefferson (Thomas) Lab. Computer Center, Newport News, VA, USA<br />

Concepts for the JLAB Ampere-Class CW Cryomodule<br />

Rimmer, R.; Daly, E. F.; Hicks, W. R.; Preble, J.; Stirbet, M.; January 2005; 8 pp.; In English<br />

Report No.(s): DE2005-840062; No Copyright; Avail.: National <strong>Technical</strong> Information Service (NTIS)<br />

We describe the concepts <strong>and</strong> developments underway at JLab as part of the program to develop a new CW cryomodule<br />

capable of transporting ampere-level beam currents in a compact FEL. Requirements include real-estate gradient of at least<br />

10 MV/m <strong>and</strong> very strong HOM damping to push BBU thresholds up by two or more orders of magnitude compared to<br />

existing designs. Cavity shape, HOM damping, power couplers, tuners etc. are being designed <strong>and</strong> optimized for this<br />

application. Cavity considerations include a large iris for beam halo, low-RF losses, HOM frequencies <strong>and</strong> Q’s, low peak<br />

surface fields, field flatness <strong>and</strong> microphonics. Module considerations include high packing factor, low static heat leak, image<br />

current heating of beam-line components, cost <strong>and</strong> maintainability. This module is being developed for the next generation<br />

ERL based high power FELs but may be useful for other applications such as electron cooling, electron-ion colliders,<br />

industrial processing etc.<br />

NTIS<br />

Continuous Radiation; Particle Accelerators<br />

75<br />

PLASMA PHYSICS<br />

Includes magnetohydrodynamics <strong>and</strong> plasma fusion. For ionospheric plasmas see 46 Geophysics. For space plasmas see 90<br />

Astrophysics.<br />

20060002432 Princeton Univ., NJ USA<br />

Testing Gyrokinetics on C-Mod <strong>and</strong> NSTX<br />

Redi, M. H.; Dorl<strong>and</strong>, W.; Flore, C. L.; Stutman, D.; Baumgaertel, J. A.; Jun. 2005; 12 pp.; In English<br />

Report No.(s): DE2005-841196; PPPL-4083; No Copyright; Avail.: National <strong>Technical</strong> Information Service (NTIS)<br />

Quantitative benchmarks of computational physics codes against experiment are essential for the credible application of<br />

such codes. Fluctuation measurements can provide necessary critical tests of nonlinear gyrokinetic simulations, but such<br />

require extraordinary computational resources. Linear micro-stability calculations with the GS2 (1) gyrokinetic code have<br />

been carried out for tokamak <strong>and</strong> ST experiments which exhibit internal transport barriers (ITB) <strong>and</strong> good plasma confinement.<br />

Qualitative correlation is found for improved confinement before <strong>and</strong> during ITB plasmas on Alcator C-Mod (2) <strong>and</strong> NSTX<br />

(3) with weaker long wavelength microinstabilities in the plasma core regions. Mixing length transport models are discussed.<br />

The NSTX L-mode is found to be near marginal stability for kinetic ballooning modes.<br />

NTIS<br />

Plasma Control; Tokamak Devices; Toruses<br />

20060002433 Princeton Univ., NJ USA<br />

Scaling of Kinetic Instability Induced Fast Ion Losses in NSTX<br />

Fredrickson, E. D.; Darrow, D.; Medley, S.; Menard, J.; Park, H.; Jun. 2005; 12 pp.; In English<br />

Report No.(s): DE2005-841197; PPPL-4084; No Copyright; Avail.: National <strong>Technical</strong> Information Service (NTIS)<br />

During neutral beam injection (NBI) in the National Spherical Torus Experiment (NSTX), a wide variety of fast ion driven<br />

instabilities is excited by the large ratio of fast ion velocity to Alfven velocity, together with the relatively high fast ion beta,<br />

beta(sub)f. The fast ion instabilities have frequencies ranging from a few kilohertz to the ion cyclotron frequency. The modes<br />

can be divided roughly into three categories, starting with Energetic Particle Modes (EPM) in the lowest frequency range (0<br />

to 120 kHz), the Toroidal Alfven Eigenmodes (TAE) in the intermediate frequency range (50 to 200 kHz) <strong>and</strong> the<br />

Compressional <strong>and</strong> Global Alfven Eigenmodes (CAE <strong>and</strong> GAE, respectively) from approximately equal to 300 kHz up to the<br />

ion cyclotron frequency. Each of these categories of modes exhibits a wide range of behavior, including quasi-continuous<br />

213

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!