Simultaneous projection and detection system of four different frequencies for microwave imaging reflectometry in Large Helical Device

Yoshinaga, T.; Nagayama, Y.; Kuwahara, D.; Takahashi, Hayato; Yamaguchi, Soichiro; Kogi, Y.; Tsuji‐Iio, S.; Mase, A.

doi:10.1063/1.3491197

Cited by 10 publications

(12 citation statements)

References 20 publications

(19 reference statements)

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“…This paper presents the 3D MIR system in LHD. This system consists of 2D microwave imaging device, 10,11 four frequency microwave source, 12 microwave imaging optics with adjustable mirror, 13 and electronics for intermediate frequency (IF) amplification, frequency separation and quadrature detection. By using the 3D MIR, 3D structure of the edge harmonic oscillation (EHO) is observed.…”

Section: Introductionmentioning

confidence: 99%

Development of 3D microwave imaging reflectometry in LHD (invited)

Nagayama

Kuwahara

Yoshinaga

et al. 2012

Review of Scientific Instruments

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Three-dimensional (3D) microwave imaging reflectometry has been developed in the large helical device to visualize fluctuating reflection surface which is caused by the density fluctuations. The plasma is illuminated by the probe wave with four frequencies, which correspond to four radial positions. The imaging optics makes the image of cut-off surface onto the 2D (7 × 7 channels) horn antenna mixer arrays. Multi-channel receivers have been also developed using micro-strip-line technology to handle many channels at reasonable cost. This system is first applied to observe the edge harmonic oscillation (EHO), which is an MHD mode with many harmonics that appears in the edge plasma. A narrow structure along field lines is observed during EHO.

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Section: Introductionmentioning

confidence: 99%

Development of 3D microwave imaging reflectometry in LHD (invited)

Nagayama

Kuwahara

Yoshinaga

et al. 2012

Review of Scientific Instruments

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“…A combined system of MIR and ECEI (electron cyclotron emission imaging) as shown in Fig. 1 has been applied to the Large Helical Device (LHD) [11][12][13]. The MIR system uses 4 different frequency sources in order to obtain the information at 4 radial positions.…”

Section: Microwave/millimeter-wave System With Quasi-optical Transmission Linementioning

confidence: 99%

“…The MIR system uses 4 different frequency sources in order to obtain the information at 4 radial positions. The sources are obtained as follows [13]. The 4 frequencies at 750, 983, 1183 and 1450 MHz from the crystal oscillators are separately up-converted with the 18.33 MHz from the crystal oscillator.…”

Section: Microwave/millimeter-wave System With Quasi-optical Transmission Linementioning

confidence: 99%

Reflectometric measurement of plasma imaging and applications

et al. 2012

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Progress in microwave and millimeter-wave technologies has made possible advanced diagnostics for application to various fields, such as, plasma diagnostics, radio astronomy, alien substance detection, airborne and spaceborne imaging radars called as synthetic aperture radars, living body measurements. Transmission, reflection, scattering, and radiation processes of electromagnetic waves are utilized as diagnostic tools. In this report we focus on the reflectometric measurements and applications to biological signals (vital signal detection and breast cancer detection) as well as plasma diagnostics, specifically by use of imaging technique and ultra-wideband radar technique.

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“…With multiple detectors and multiple operating frequencies, MIR promises to provide a capability for diagnosis of spatially localized density fluctuations comparable to that realized by ECEI for temperature fluctuations. The MIR system on LHD [25][26][27] represents a groundbreaking achievement in 3D imaging of density fluctuations, and provides data key to understanding the transport properties of this stellarator device. At the heart of the LHD MIR system is a horn mixer array (HMA) which combines well-characterized pyramidial horn antennas, Schottky diode mixers, and IF amplification in a single shielded and expandable unit.…”

Section: Recent Advancements In Mirmentioning

confidence: 99%

Recent Progress on Microwave Imaging Technology and New Physics Results

Tobias

Luhmann

Domier

et al. 2011

Plasma and Fusion Research

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Techniques for visualizing turbulent flow in nature and in the laboratory have evolved over half a millennium from Leonardo da Vinci's sketches of cascading waterfalls to the advanced imaging technologies which are now pervasive in our daily lives. Advancements in millimeter wave imaging have served to usher in a new era in plasma diagnostics, characterized by ever improving 2D, and even 3D, images of complex phenomena in tokamak and stellarator plasmas. Examples at the forefront of this revolution are electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR). ECEI has proved to be a powerful tool as it has provided immediate physics results following successful diagnostic installations on TEXTOR, ASDEX-U, DIII-D, and KSTAR. Recent results from the MIR system on LHD are demonstrating that this technique has the potential for comparable impact in the diagnosis of electron density fluctuations. This has motivated a recent resurgence in MIR research and development, building on a prototype system demonstrated on TEXTOR, toward the realization of combined ECEI/MIR systems on DIII-D and KSTAR for simultaneous imaging of electron temperature and density fluctuations. The systems discussed raise the standard for fusion plasma diagnostics and present a powerful new capability for the validation of theoretical models and numerical simulations.

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Simultaneous projection and detection system of four different frequencies for microwave imaging reflectometry in Large Helical Device

Cited by 10 publications

References 20 publications

Development of 3D microwave imaging reflectometry in LHD (invited)

Development of 3D microwave imaging reflectometry in LHD (invited)

Reflectometric measurement of plasma imaging and applications

Recent Progress on Microwave Imaging Technology and New Physics Results

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