System-on-chip integrated circuit technology applications on the DIII-D tokamak for multi-field measurements

Zheng, Yuan; Yu, Guangyang; Chen, J.; Chen, Y.; Zhu, Yunbin; Domier, C.W.; Brower, Derek; Luhmann, Neville C.

doi:10.1088/1748-0221/17/01/c01013

Cited by 5 publications

(1 citation statement)

References 16 publications

(19 reference statements)

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“…In this paper, synthetic modeling [17,18] of the ECE radiation is applied to interpret the ECEI measurements of EHO and QCM. ECEI is a powerful imaging diagnostic technique [19][20][21] that can characterize the temperature fluctuations of core MHD, such as sawteeth [22,23], tearing modes [24][25][26] and Alfven eigenmodes [27][28][29][30][31]. The method is also applied to image the nonlinear fluctuation behavior associated with ELMs [32,33] and edge turbulence [34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

ECEI characterization of pedestal fluctuations in quiescent H-mode plasmas in DIII-D

Nazikian²,

Zhu³

et al. 2022

Plasma Phys. Control. Fusion

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Electron cyclotron emission imaging (ECEI) is employed to characterize the magneto hydraulics dynamics (MHD) fluctuations at the quiescent H-mode pedestals in DIII-D. Pedestal MHD fluctuations cause ECE radiation temperature fluctuations δ T e ,rad in both the pedestal and scrape-off-layer (SOL). A synthetic ECE platform is utilized for detailed interpretation of the ECEI signals in the SOL and pedestal regions. It is observed that the ECE radiation δ T e ,rad , which is located in the SOL region according to the cold and optically thick plasma resonance assumption, is extremely sensitive to MHD radial displacements near the separatrix, exhibiting radiation inversion to δ T e ,rad at the pedestal. Here, the radiation inversion refers to the opposite phase between the radiation fluctuation at the pedestal and the radiation fluctuation at the SOL. Consequently, the quasi-coherent MHD (QCM), which displays a radiation inversion, is found to be consistent with an MHD radial structure that has a strong displacement near the separatrix. In contrast, the edge harmonic oscillation (EHO), which displays weak or no inversion, is found to be consistent with an MHD radial displacement structure peaking at the pedestal top. The ECEI data, interpreted with synthetic ECE, are in qualitative agreement with beam emission spectroscopy measurements on DIII-D for the relative radial extent and localization of the EHO and QCM. The high sensitivity of ECE radiation to separatrix displacements can be used to detect turbulence or MHD fluctuations near the separatrix, which may affect the transport across the separatrix and the wetted area in the divertor. The δ T e ,rad inversion measured with an ECE or ECEI system potentially provides important information on the magnetic field B sep at the separatrix, which helps constrain the pedestal equilibrium reconstruction and achieve an unambiguous mapping of the ECE/ECEI system with respect to the separatrix.

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Section: Introductionmentioning

confidence: 99%

ECEI characterization of pedestal fluctuations in quiescent H-mode plasmas in DIII-D

Nazikian²,

Zhu³

et al. 2022

Plasma Phys. Control. Fusion

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System-on-chip approach microwave imaging reflectometer on DIII-D tokamak

Zhu

Chen

et al. 2022

Review of Scientific Instruments

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System-on-chip millimeter wave integrated circuit technology is used on the two-dimensional millimeter-wave imaging reflectometer (MIR) upgrade for density fluctuation imaging on the DIII-D tokamak fusion plasma. Customized CMOS chips have been successfully developed for the transmitter module and receiver module array, covering the 55–75 GHz working band. The transmitter module has the capability of simultaneously launching eight tunable probe frequencies (>0 dBm output power each). The receiver enclosure contains 12 receiver modules in two vertical lines. The quasi-optical local oscillator coupling of previous MIR systems has been replaced with an internal active frequency multiplier chain for improved local oscillator power delivery and flexible installation in a narrow space together with improved shielding against electromagnetic interference. The 55–75 GHz low noise amplifier, used between the receiver antenna and the first-stage mixer, significantly improves module sensitivity and suppresses electronics noise. The receiver module has a 20 dB gain improvement compared with the mini-lens approach and better than −75 dBm sensitivity, and its electronics noise temperature has been reduced from 55 000 K down to 11 200 K. The V-band MIR system is developed for co-located multi-field investigation of MHD-scale fluctuations in the pedestal region with W-band electron cyclotron emission imaging on DIII-D tokamak.

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Diagnosing the pedestal magnetic field and magnetohydrodynamics radial structure with pedestal–scrape of layer electron cyclotron emission radiation inversion in H-mode plasma (invited)

Zhu

Austin

et al. 2022

Review of Scientific Instruments

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Forward modeling is used to interpret inversion patterns of the pedestal–Scrape of Layer (SOL) Electron Cyclotron Emission (ECE) in DIII-D H-mode experiments. The modeling not only significantly improves the ECE data interpretation quality but also leads to the potential measurements of (1) the magnetic field strength |B| at the separatrix, (2) the pedestal |B| evolution during an inter-Edge Localized Mode (ELM) period, and (3) the pedestal Magnetohydrodynamics (MHD) radial structure. The ECE shine-through effect leads to three types of pedestal–SOL radiation inversions that are discussed in this paper. The first type of inversion is the non-monotonic T e, rad profile with respect to the major radius. Using the ECE frequency at the minimum T e, rad, the inversion can be applied to measure the magnetic field |B| at the separatrix and calibrate the mapping of the ECE channels with respect to the separatrix. The second type of inversion refers to the opposite phase between the radiation fluctuations δT e, rad at the pedestal and SOL. This δT e, rad phase inversion is sensitive to density and temperature fluctuations at the pedestal foot and, thus, can be used to qualitatively measure the MHD radial structure. The third type of inversion appears when the pedestal and SOL T e, rad evolve in an opposite trend, which can be used to infer the pedestal |B| field change during an inter-ELM period. The bandwidth effect on measuring δT e, rad due to pedestal MHD is also investigated in the radiation modeling.

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System-on-chip integrated circuit technology applications on the DIII-D tokamak for multi-field measurements

Cited by 5 publications

References 16 publications

ECEI characterization of pedestal fluctuations in quiescent H-mode plasmas in DIII-D

ECEI characterization of pedestal fluctuations in quiescent H-mode plasmas in DIII-D

System-on-chip approach microwave imaging reflectometer on DIII-D tokamak

Diagnosing the pedestal magnetic field and magnetohydrodynamics radial structure with pedestal–scrape of layer electron cyclotron emission radiation inversion in H-mode plasma (invited)

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