Evaluation of the operating space for density fluctuation measurements employing 2D imaging reflectometry

Abstract

Microwave imaging reflectometry provides broad poloidal coverage as a density fluctuation measurement tool. 2D imaging systems are evaluated for DIII-D relevant conditions using a full-wave reflectometer code, FWR2D. Reasonable correlation of the synthetic diagnostic signal with density fluctuations at the plasma cutoff surface for a wide range of fluctuation parameters is evaluated and achieved for coherent oscillations; also the frequency spectra are compared for relevant fluctuations. The consequences of non-idealities inherent to imaging fluctuations away from the plasma midplane, where receiving antennas view the plasma cutoff at oblique angles, are evaluated for the optimization of these systems.

Estimation of the radial size and density fluctuation amplitude of edge localized modes using microwave interferometer array

“…In order to determine the radial size and density fluctuation amplitude of the observed ELMs, the dependence of the ∆ϕ amplitude on the radial size and fluctuation amplitude of ELMs has been investigated using a two dimensional full-wave simulation code FWR2D [29]. The code simulates electromagnetic wave propagation and reflection through inhomogeneous plasma [34,[45][46][47][48] by solving the time-dependent scalar wave equation for the electric field E(x, y, t),…”

Millimeter-wave imaging of magnetic fusion plasmas: technology innovations advancing physics understanding

“…DBF allows finely-tuned alignment that tracks changing conditions in real time, thereby facilitating studies including disruption precursors. When complemented by new software and advanced SDM capabilities [56][57][58][59][60], these technologies will enable compact and low-noise transceiver systems with realtime, fast tracking capability (as shown in figure 7) to address critical fusion plasma physics issues, including the ITER baseline scenario [61][62][63] and QH-mode [50,[64][65][66]. For each development, the advanced technology finds immediate application as 'plug-in' modules, which can be integrated into existing mm-wave imaging systems to provide enhanced capability.…”

“…As shown in figure 22, the synthetic diagnostics analysis couples quasi-optical modeling of the antennas and lens system, plasma simulation codes generating linear and nonlinear time-dependent plasma fluctuations, and 2D/3D full-wave modeling of the plasma-wave interaction at the microwave reflection layer. This capability has been used extensively in the design of MIR diagnostics [58,59]. Furthermore, it has been used to make a comparison between linear, time-dependent M3D-C1 simulations of the edge harmonic oscillation (EHO) on DIII-D and recently collected MIR data [50].…”

The general optics structure of millimeter-wave imaging diagnostic on TOKAMAK

“…The fusion plasma cannot be treated simply as vacuum because of the interaction between the microwaves and the plasma, especially in the cut-off region. Consequently, the modeling and design of the optics utilizes the plasma simulation code FWR [19], which calculates the interaction between the plasma and the microwaves propagating through the plasma. The 2S distributions of the toroidal field and the plasma electron density are important inputs for modeling using the FWR simulation process.…”