Design of a low frequency, density profile reflectometer system for the MAST-U spherical tokamak.

Validated and accurate edge profiles (temperature, density, etc.) are vitally important to the Mega Ampere Spherical Tokamak Upgrade (MAST-U) divertor and confinement effort. Density profile reflectometry has the potential to significantly add to the measurement capabilities currently available on MAST-U (e.

New millimeter-wave diagnostics to locally probe internal density and magnetic field fluctuations in National Spherical Torus Experiment-Upgrade (invited).

A set of new millimeter-wave diagnostics will deliver unique measurement capabilities for National Spherical Torus Experiment-Upgrade to address a variety of plasma instabilities believed to be important in determining thermal and particle transport, such as micro-tearing, global Alfvén eigenmodes, kinetic ballooning, trapped electron, and electron temperature gradient modes. These diagnostics include a new integrated intermediate-k Doppler backscattering (DBS) and cross-polarization scattering (CPS) system (four channels, 82.5-87 GHz) to measure density and magnetic fluctuations, respectively.

A new synthetic correlation electron cyclotron emission diagnostic for validating nonlinear gyrokinetic simulations of electron temperature turbulence.

To validate nonlinear gyrokinetic simulations of electron temperature turbulence, the experimental correlation electron cyclotron emission (CECE) measurements are to be compared using a synthetic CECE diagnostic, which generates modeled CECE measurement quantities by implementing realistic measurement parameters (e.g., spatial and wavenumber resolutions, radial location, etc.

A Q-band frequency tunable Doppler backscattering (DBS) system for pedestal and scrape-off layer density fluctuation and flow measurements in the DIII-D tokamak.

We present the design and laboratory tests for a new Q-band frequency tunable Doppler backscattering (DBS) system suitable for probing poloidal wavenumber kñ = 6-8 cm-1 density fluctuations and their flow velocities in the pedestal and scape-off layer (SOL) of the DIII-D tokamak. This system will provide new measurements in the increasingly important and under-diagnosed far pedestal and SOL plasma regions. These results are important for experimental transport studies and necessary for the validation of transport models, both of which are important to fusion energy research.

A novel Doppler backscattering (DBS) system to simultaneously measure radio frequency plasma fluctuations and low frequency turbulence.

A novel quadrature Doppler Backscattering (DBS) system has been developed and optimized for the E-band (60-90 GHz) frequency range using either O-mode or X-mode polarization in DIII-D plasmas. In general, DBS measures the amplitude of density fluctuations and their velocity in the lab frame. The system can simultaneously monitor both low-frequency turbulence (f < 10 MHz) and radiofrequency plasma density fluctuations over a selectable frequency range (20-500 MHz).