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  • INSTRUMENTATION AND PHOTOGRAPHY  (1)
  • electron cyclotron resonance heating (ECRH)  (1)
  • 1985-1989  (2)
  • 1970-1974
  • 1965-1969
Collection
Publisher
Years
  • 1985-1989  (2)
  • 1970-1974
  • 1965-1969
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    International journal of infrared and millimeter waves 6 (1985), S. 459-470 
    ISSN: 1572-9559
    Keywords: high-power millimeter waves ; gyrotron ; electron cyclotron resonance heating (ECRH) ; overmoded waveguide systems ; mode conversion ; linearly polarized narrow pencil beam
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This work reports calculations and measurements on mode converters for the transformation of TEOn gyrotron mode mixtures (primarily TEO2) into the linearly polarized HE11 hybrid mode at 70 GHz. This mode is ideal for quasi-optical launching systems for ECRH of plasmas. Mode transducers with axisymmetric radius perturbations convert the gyrotron TEOn mode composition into the TEO1 mode. Proper matching of the phase differences between the various modes and of the perturbation amplitudes of the several converter sections is required. The TEO1 wave is used for long-distance transmission through smooth-walled overmoded waveguides. A mode converter with constant diameter and periodically perturbed curvature transfers the unpolarized TEO1 mode into the polarized TE11 wave. The experimentally determined ΣTEOn-to-TEO1 conversion efficiency is (98.5±1)% (99% predicted) while the TEO1-to-TE11 transformer has a (94±2)% efficiency (93% theoretically); ohmic losses are included. The “Gaussian-like” HE11 mode with axisymmetric power distribution and almost no cross polarization is produced in a circumferentially corrugated TE11-to-HE11 mode transducer with a measured conversion efficiency of (98.3±1.5)% (98.5% predicted). The overall efficiency of the complete mode converter system in the desired mode was determined to be (91±2.5)%. High-power operation (200kW, 100ms) has been successfully demonstrated.
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2019-07-13
    Description: The technique of obtaining quantitative data from high resolution soft X-ray photographic images produced by grazing incidence optics was successfully developed to a high degree during the AS&E Solar Research Sounding Rocket Program and the S-054 X-Ray Spectrographic Telescope Experiment Program on Skylab. Continued use of soft X-Ray photographic imaging in sounding rocket flights of the AS&E High Resolution Solar Soft X-Ray Imaging Payload has provided opportunities to further develop these techniques. The developments discussed include: (1) the calibration and use of an inexpensive, commercially available microprocessor controlled drum type film processor for photometric film development, (2) the use of Kodak Technical Pan 2415 film and Kodak SO-253 High Speed Holographic film for improved resolution, and (3) the application of a technique described by Cook, Ewing, and Sutton (1988) for determining the film characteristics curves from density histograms of the flight film. Although the superior sensitivity, noise level, and linearity of microchannel plate and CCD detectors attracts the development efforts of many groups working in soft X-ray imaging, the high spatial resolution and dynamic range as well as the reliability and ease of application of photographic media assures the continued use of these techniques in solar X-ray astronomy observations.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: EUV, X-ray, and Gamma-Ray Instrumentation for Astronomy and Atomic Physics; Aug 07, 1989 - Aug 11, 1989; San Diego, CA; United States
    Format: text
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