Development and Application of Millimeter-Wave Imaging Radar.

Mase, A.; Kogi, Y.; Yamamoto, A.; Ohashi, Masamichi; Osako, Shuhei; Bruskin, L. G.; Hōjō, H.

doi:10.1585/jspf.78.439

Cited by 6 publications

(2 citation statements)

References 12 publications

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“…The quadrature-type detection system provides the phase difference between two IF signals that is proportional to the line density of the plasma. Figure 3 shows an example of the measurement result, that is, time evolution of the 2D linedensity profiles [4]. When the electron cyclotron resonance heating (ECRH) power is applied to the plug/barrier plasma at t = 140 ms, the confining potential is created near the position of z = 962 cm where the magnetic field strength equals to 1 T. At the region of z = 971 cm where the imaging system is installed, the loss particles decrease due to the effect of axial plugging.…”

Section: Interferometrymentioning

confidence: 99%

Advancements of microwave diagnostics in magnetically confined plasmas

Mase

Kogi

Ito

et al. 2009

Plasma Devices and Operations

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Microwave to millimeter-wave diagnostic techniques such as interferometry, reflectometry, scattering and radiometry have been powerful tools for diagnosing magnetically confined plasmas. Recent advances in electronic devices and components together with computer technology have enabled the development of advanced diagnostics in microwave to millimeter-wave region. The two-dimensional and three-dimensional profiles of plasma density/temperature and dynamic behaviors of their fluctuations are measured by using the advanced diagnostic systems. The measurements have clarified the physics issues such as stability, wave phenomena and fluctuation-induced transport. We report here on the representative microwave diagnostics and their contribution to plasma confinement physics.

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Section: Interferometrymentioning

confidence: 99%

Advancements of microwave diagnostics in magnetically confined plasmas

Mase

Kogi

Ito

et al. 2009

Plasma Devices and Operations

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“…The second method is to apply an ultrashort pulse as a source, which is an advantage in density profile measurements due to its broad frequency spectra, for example, from dc to 26 GHz. [3][4][5] We report here the application of the ultrashort pulse reflectometry ͑USPR͒ to an inductively coupled plasma ͑ICP͒ and the data analysis method named signal record analysis ͑SRA͒, 6 which can introduce less receiver channel requirements and reliable profile reconstruction. In addition, this article describes methods to generate a pulse with higher frequency up to 90 GHz and a preliminary test of the reflectometry for high density plasmas.…”

Section: Introductionmentioning

confidence: 99%

Ultrashort-pulse reflectometry for steady-state plasmas

Kogi

Mase

Ohsako

et al. 2003

Review of Scientific Instruments

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Design of an X-mode fast-scanning reflectometry for edge density profile measurement on HT-7 tokamak Rev. Sci. Instrum. 74, 1522 (2003; 10.1063/1.1527253 Millimeter-wave reflectometry for electron density profile and fluctuation measurements on NSTX Rev. Sci. Instrum. 72, 348 (2001); 10.1063/1.1329657 Ultrashort pulse reflectometry for electron density profile measurements on SSPX Rev. Sci. Instrum. 72, 332 (2001); 10.1063/1.1308999Preliminary electron density profile and fluctuation measurements on GAMMA 10 using ultrashort-pulse reflectometry Rev.An ultrashort-pulse reflectometry ͑USRM͒ has been applied to the inductively coupled steady-state plasma ͑ICP͒ for density profile measurement. A reflected wave from ICP is directly recorded into a digitizing sampling scope and is analyzed by the signal record analysis ͑SRA͒ method. From repetition of the measurement, we have obtained the time evolution of the density profile. In order to apply the USRM and SRA method to high density plasmas such as core region of the Large Helical Device plasma, generation of the pulse with higher frequency up to 90 GHz is essential. We have utilized a frequency upconverter and an active doubler for this purpose. We confirmed the generation of the upconverted pulse in the range of 60-90 GHz and the second-harmonic frequency in the range of 26 -40 GHz. Time of flight measurements have been preliminarily performed with a metal target.

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