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Your search keyword '"Wilgen, J."' showing total 22 results
Start Over Author "Wilgen, J." Journal review of scientific instruments
22 results on '"Wilgen, J."'

5. Addendum to papers from the NSTX Team, published in Review of Scientific Instruments

Author

Gates, D. A., primary, Kessel, C., additional, Menard, J., additional, Taylor, G., additional, Wilson, J. R., additional, Bell, M. G., additional, Bell, R. E., additional, Bernabei, S., additional, Bialek, J., additional, Biewer, T., additional, Blanchard, W., additional, Boedo, J., additional, Bush, C., additional, Carter, M. D., additional, Choe, W., additional, Crocker, N., additional, Darrow, D. S., additional, Davis, W., additional, Delgado-Aparicio, L., additional, Diem, S., additional, Ferron, J., additional, Field, A., additional, Foley, J., additional, Fredrickson, E. D., additional, Gibney, T., additional, Harvey, R., additional, Hatcher, R. E., additional, Heidbrink, W., additional, Hill, K., additional, Hosea, J. C., additional, Jarboe, T. R., additional, Johnson, D. W., additional, Kaita, R., additional, Kaye, S., additional, Kubota, S., additional, Kugel, H. W., additional, Lawson, J., additional, LeBlanc, B. P., additional, Lee, K. C., additional, Levinton, F., additional, Maingi, R., additional, Manickam, J., additional, Maqueda, R., additional, Marsala, R., additional, Mastrovito, D., additional, Mau, T. K., additional, Medley, S. S., additional, Meyer, H., additional, Mikkelsen, D. R., additional, Mueller, D., additional, Munsat, T., additional, Nelson, B. A., additional, Neumeyer, C., additional, Nishino, N., additional, Ono, M., additional, Park, H., additional, Park, W., additional, Paul, S., additional, Peebles, T., additional, Peng, M., additional, Phillips, C., additional, Pigarov, A., additional, Pinsker, R., additional, Ram, A., additional, Ramakrishnan, S., additional, Raman, R., additional, Rasmussen, D., additional, Redi, M., additional, Rensink, M., additional, Rewoldt, G., additional, Robinson, J., additional, Roney, P., additional, Roquemore, L., additional, Ruskov, E., additional, Ryan, P., additional, Sabbagh, S. A., additional, Schneider, H., additional, Skinner, C. H., additional, Smith, D. R., additional, Sontag, A., additional, Soukhanovskii, V., additional, Stevenson, T., additional, Stotler, D., additional, Stratton, B., additional, Stutman, D., additional, Swain, D., additional, Synakowski, E., additional, Takase, Y., additional, Tritz, K., additional, von Halle, A., additional, Wade, M., additional, White, R., additional, Wilgen, J., additional, Williams, M., additional, Zhu, W., additional, Zweben, S. J., additional, Akers, R., additional, Beiersdorfer, P., additional, Betti, R., additional, and Bigelow, T., additional

Published
2009
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13. Possible integrated diagnostic set for ion cyclotron heating for the tokamak physics experiment (TPX) (abstract)a)

Author

Rasmussen, D. A., primary, Thomas, C. E., additional, Swain, D. W., additional, Batchelor, D. B., additional, Caughman, J. B., additional, Colchin, R. J., additional, Goulding, R. H., additional, Hanson, G. R., additional, Hoffman, D. J., additional, Isler, R. C., additional, Jaeger, E. F., additional, and Wilgen, J. B., additional

Published
1995
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16. Te(R,t) measurements using electron Bernstein wave thermal emission on NSTX.

Author

Diem, S. J., Taylor, G., Efthimion, P. C., LeBlanc, B. P., Carter, M., Caughman, J., Wilgen, J. B., Harvey, R. W., Preinhaelter, J., and Urban, J.

Subjects
PLASMA gases, MAGNETIC fields, ELECTRON cyclotron resonance sources, ELECTRICAL harmonics, RADIOMETERS, PHYSICS
Abstract

The National Spherical Torus Experiment (NSTX) routinely studies overdense plasmas with ne of (1–5)×1019 m-3 and total magnetic field of <0.6 T, so that the first several electron cyclotron harmonics are overdense. The electrostatic electron Bernstein wave (EBW) can propagate in overdense plasmas, exhibits strong absorption, and is thermally emitted at electron cyclotron harmonics. These properties allow thermal EBW emission to be used for local Te measurement. A significant upgrade to the previous NSTX EBW emission diagnostic to measure thermal EBW emission via the oblique B-X-O mode conversion process has been completed. The new EBW diagnostic consists of two remotely steerable, quad-ridged horn antennas, each of which is coupled to a dual channel radiometer. Fundamental (8–18 GHz) and second and third harmonic (18–40 GHz) thermal EBW emission and polarization measurements can be obtained simultaneously. [ABSTRACT FROM AUTHOR]

Published
2006
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17. Technique for measuring D2 pellet mass loss through a curved guide tube using two microwave cavity detectors.

Author

Combs, S. K., Caughman, J. B. O., and Wilgen, J. B.

Subjects
MICROWAVES, ELECTROMAGNETIC waves, DETECTORS, MASS loss (Astrophysics), TOKAMAKS, FUSION reactors
Abstract

Two microwave cavity mass detectors have been used to measure the mass loss of deuterium (D2) pellets transported through a curved guide tube. The test tube was a mock-up of the pellet injection guide tube for the proposed ITER experiment, which will be used to transport pellets, including deuterium-tritium (D-T), from the pellet acceleration device to the inner wall (or magnetic high-field side) of the large tokamak for pellet injection and core fueling of plasmas. An accurate estimate of the mass loss is particularly important for D-T injection, because the inventory of the radioactive isotope (T) for ITER is limited and accountability and recycling will be crucial issues. In the laboratory, frozen cylindrical D2 pellets of nominal 5.3-mm diameter were shot through the stainless steel test tube (≈10 m in length and 10-mm inside diameter), with each end equipped with a microwave cavity. As the pellet passes through each tuned microwave cavity, the peak output signal from the electronics is directly proportional to the pellet mass. An absolute calibration of the cavities, which can be problematic, is not needed for the nondestructive technique described here. Instead, a cross calibration of the two cavities with pellets of varying masses provides the relationship to determine mass loss more precisely than any other technique previously reported. In addition, the individual output signals from the cavities can be used to identify intact pellets (a single signal peak) or broken pellets (multiple signal peaks). For the pellet speed range tested in this study (100–500 m/s), the mass loss for intact pellets was directly dependent on the pellet speed, with ≈10% mass loss at 300 m/s. The microwave cavities and the associated electronics, as well as some basic theory, are described; calibration and experimental data are presented and discussed. [ABSTRACT FROM AUTHOR]

Published
2006
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19. First results with amplitude modulation reflectometry on the PBX-M tokamak.

Author

de la Luna, E., Sanchez, J., Zhuravlev, V., Garcia-Cortes, I., Hanson, G. R., Wilgen, J. B., Harris, J. H., Dunlap, J., Kaita, R., Leblanc, B., Tynan, G. R., Schmitz, L., and Blush, L.

Subjects
ELECTRON distribution, TOKAMAKS, REFLECTOMETER
Abstract

Obtains electron density profile measurements on PBX-M tokamaks by amplitude modulation reflectometry. Measurement of the time delay obtained from the phase delay of the modulating envelope; Operation of the system with the extraordinary mode.

Published
1995

20. ECE diagnostic for ATF.

Author

Bell, G. L., Gandy, R. F., Wilgen, J. B., and Rasmussen, D. A.

Subjects
NUCLEAR facilities, PLASMA diagnostics, ELECTRON temperature
Abstract

Electron cyclotron emission (ECE) from the Advanced Toroidal Facility (ATF) torsatron will allow measurement of plasma electron temperature. For low-field operation (0.95 T) the second harmonic is cut off at a relatively low density; therefore, third-harmonic emission from 67 to 83 GHz is used to yield central electron temperatures. At high-field operation (1.9 T) secondharmonic emission from 82 to 114 GHz is optically thick and can provide T[sub e](r) information. A vertical view of the saddle-point geometry of the ATF mod B spatial contours provides a line of sight along which the mod B contours are symmetric with respect to flux surfaces. A single hornlens viewing beam system with a vertical view is designed to cover the entire 67-114-GHz range, providing a spot size on the order of 6 cm. Radiation will be delivered to one of three waveguide mixers by C-band waveguide. Each of the three mixers covers a 16-GHz segment of the emission spectrum, downconverting it to the 2-18-GHz intermediate-frequency band, where it is processed by a 16-channel array of bandpass filters, providing 1-GHz frequency resolution. [ABSTRACT FROM AUTHOR]

Published
1988
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22. Scrape-off layer reflectometer for Alcator C-Mod.

Author

Lau C, Hanson G, Wilgen J, Lin Y, and Wukitch S

Abstract

A swept-frequency X-mode reflectometer is being built for Alcator C-Mod to measure the scrape-off layer density profiles at the top, middle, and bottom locations in front of both the new lower hybrid launcher and the new ion cyclotron range of frequencies antenna. The system is planned to operate between 100 and 146 GHz at sweep rates from 10 μs to 1 ms, and will cover a density range of approximately 10(16)-10(20) m(-3) at B(0)=5-5.4 T. To minimize the effects of density fluctuations, both differential phase and full phase reflectometry will be employed. Design, test data, and calibration results of this electronics system will be discussed. To reduce attenuation losses, tallguide (TE(01)) will be used for most of the transmission line system. Simulations of high mode conversion in tallguide components, such as e-plane hyperbolic secant radius of curvature bends, tapers, and horn antennas will be shown. Experimental measurements of the total attenuation losses of these components in the lower hybrid waveguide run will also be presented.

Published
2010
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