A5038176826- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Nuclear Physics and Applications
- Plasma Diagnostics and Applications
- Atomic and Subatomic Physics Research
- Solar and Space Plasma Dynamics
- Dust and Plasma Wave Phenomena
- Electrohydrodynamics and Fluid Dynamics
- Physics of Superconductivity and Magnetism
- Gyrotron and Vacuum Electronics Research
- Photocathodes and Microchannel Plates
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
Dalian University of Technology
2024
University of California, Davis
2010-2015
A new electron cyclotron emission imaging diagnostic has been commissioned on the DIII-D tokamak. Dual detector arrays provide simultaneous two-dimensional images of Te fluctuations over radially distinct and reconfigurable regions, each with both vertical radial zoom capability. total 320 (20 vertical×16 radial) channels are available. First data from this demonstrate acquisition coherent temperature as low 0.1% excellent clarity spatial resolution. Details features capabilities presented.
The two-dimensional mm-wave imaging reflectometer (MIR) on DIII-D is a multi-faceted device for diagnosing electron density fluctuations in fusion plasmas. Its multi-channel, multi-frequency capabilities and high sensitivity permit visualization quantitative diagnosis of perturbations, including correlation length, wavenumber, mode propagation velocity, dispersion. MIR are made possible with 12 vertically separated sightlines four-frequency operation (corresponding to four radial channels)....
Abstract Imaging diagnostics, such as Electron Cyclotron Emission (ECEI) and Microwave Reflectometry (MIR), exhibit unique characteristics that make them particularly well suited to the validation of theoretical models for plasma instabilities turbulent fluctuations. A 2‐D picture phenomena is provided unambiguously, from localized, time‐resolved measurements. After more than a decade development successful demonstrations on RTP [1,2] TEXTOR [3, 4, 5, 6], ECEI has come into maturity an...
High confinement (H-mode) discharges on the DIII-D tokamak are routinely subject to formation of long-lived, non-disruptive magnetic islands that degrade and limit fusion performance. Simultaneous, 2D measurement electron temperature fluctuations in core edge regions allows for reconstruction radially resolved poloidal mode number spectrum phase global plasma response associated with these modes. Coherent, n = 2 excursions boundary found be result coupling an 2, kink-like which arises locked...
ECE Imaging (ECEI) systems have been installed and are presently operating on the KSTAR, DIII-D, ASDEX-UG, HT-7 tokamaks. All inherently 2-D systems, collect-ing second harmonic radiation to form temporally-resolved localized Teimages. System resolutions range from 16 × 8 (HT-7 ASDEX-UG) 20 (DIII-D) 24 (KSTAR), with a spatial resolution as low 1.0 cm (vertical) by 0.9 (radial), video bandwidths up 400 kHz. Noise drift performance of ECEI KSTAR DIII-D were significantly improved in 2011 new...
Two-dimensional observations of spatially coherent electron temperature fluctuations at drift-wave scales (k ∼ 1 cm−1) have been made using the cyclotron emission imaging diagnostic on DIII-D tokamak. These measurements enable extraction spectral properties, including poloidal dispersion relations. Temperature fluctuation levels are found to be Tẽ/⟨Te⟩=1.2%, and phase velocity is constant across frequencies, consistent with modes having real frequencies low compared rotation-induced Doppler...
Non-axisymmetric equilibria arise in DIII-D discharges that are subjected to magnetic perturbation by 3D coils. But, shaping of the entire plasma, including boundary, also occurs rotating fluid frame saturated internal islands (Tobias et al 2013 Plasma Phys. Control. Fusion 55 095006). This is advantageous since and kink responses rotate near velocity plasma easily diagnosed, while static perturbations laboratory not. The helicity perturbed shape same both rotational frames reference, making...
Abstract The self-excited second harmonic in radio-frequency capacitively coupled plasma was significantly enhanced by adjusting the external variable capacitor. At a lower pressure of 3 Pa, excitation caused an abnormal transition electron energy probability function, resulting abrupt changes density and temperature. Such function as well temperature were not observed at higher 16 Pa under similar changes. phenomena are related to influence on stochastic heating, which is determined both...
Summary form only given. Electron cyclotron emission imaging (ECEI) is a passive radiometric diagnostic technique in which broadband ECE radiation collected by one or more 1-D array to generate 2-D localized, time-resolved electron temperature T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</sub> images. Translatable optics allow each independently focus on different portions of the plasma, forming up 24 (v) × 8 (h) = 192 channel images...
Summary form only given. The NSTX high-k scattering system employs a 282 GHz probe beam, with steerable reflective optics spanning angles in the range of ±20°, wavenumber coverage up to 30 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> k <sub xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> and 7 xmlns:xlink="http://www.w3.org/1999/xlink">θ</sub> . xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> This has provided wealth physics...