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

“…The integration of System-on-Chip (SoC) technology into fusion plasma millimeter-wave diagnostics, beginning in 2014, has marked a significant milestone in the field of plasma research [35][36][37][38][39][40][41][42]. SoC systems have numerous advantages over traditional waveguide and surface mount implementations and are indeed a promising choice for mm-wave receivers [43][44][45].…”

Section: Introductionmentioning

confidence: 99%

GaN-based W-band receiver chip development for fusion plasma diagnostics

Li,

Chen,

Chen

et al. 2024

J. Inst.

2

0

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Millimeter-wave diagnostics have proven effective on various magnetic fusion devices worldwide, yet the formidable challenges posed by the harsh environments of future burning plasma devices, characterized by extreme temperatures, pressures, and radiation levels, remain a significant hurdle. To address these challenges, the utilization of wide bandgap Gallium Nitride (GaN)-based millimeter-wave diagnostics is a most promising solution for fusion reactor safety monitoring and control. A noteworthy W-band GaN-based system-on-chip receiver has been the demonstrated by employing HRL T3 40 nm GaN technology. This receiver chip, compactly designed with dimensions of 3 × 5 mm2, incorporates essential components such as the 75–110 GHz RF Low-Noise Amplifier (LNA), mixer, Intermediate Frequency (IF) amplifier, and Local Oscillator (LO) chain. This receiver chip will be packaged as a millimeter-wave receiver module and applied on the DIII-D National Fusion Facility, for fusion plasma edge shape monitoring for operational safety and dangerous disruption prediction. The laboratory measurement results have demonstrated suitable performance. This advancement is pivotal for accurate analysis of plasma behavior in the extreme conditions of burning plasma devices, driving progress in fusion research and technology.

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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

Yu

¹

,

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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Modelling of the electron cyclotron emission burst from a laboratory tokamak plasma with loss-cone maser instability

Yu,

Kramer,

Zhu

et al. 2024

J. Plasma Phys.

0

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The maser instability associated with the loss-cone distribution has been widely invoked to explain the radio bursts observed in the astrophysical plasma environment, such as aurora and corona. In the laboratory plasma of a tokamak, events reminiscent of these radio bursts have also been frequently observed as an electron cyclotron emission (ECE) burst in the microwave range ( $\mathrm{\sim }2{f_{\textrm{ce}}}$ near the last closed flux surface) during transient magnetohydrodynamic events. These bursts have a short duration of ~10 μs and display a radiation spectrum corresponding to a radiation temperature ${T_{e,\textrm{rad}}}$ of over $30\ \textrm{keV}$ while the edge thermal electron temperature ${T_e}$ is only in the range of $1\ \textrm{keV}$ . Suprathermal electrons can be generated through magnetic reconnection, and a loss-cone distribution can be generated through open stochastic field lines in the magnetic mirror of the near-edge region of a tokamak plasma. Radiation modelling shows that a sharp distribution gradient $\partial f/\partial {v_ \bot } > 0$ at the loss-cone boundary can cause a negative absorption of ECE radiation through the maser instability. The negative absorption then amplifies the radiation so that the microwave intensity is significantly stronger than the thermal value. The significant ${T_{e,\textrm{rad}}}$ from the simulations suggests the potential role of the loss-cone maser instability in generating the ECE burst in a tokamak.

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

Cited by 9 publications

References 16 publications

GaN-based W-band receiver chip development for fusion plasma diagnostics

GaN-based W-band receiver chip development for fusion plasma diagnostics

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

Modelling of the electron cyclotron emission burst from a laboratory tokamak plasma with loss-cone maser instability

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