A5100758605- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Ferroelectric and Piezoelectric Materials
- Acoustic Wave Resonator Technologies
- Fusion materials and technologies
- Multiferroics and related materials
- Superconducting Materials and Applications
- Astrophysics and Cosmic Phenomena
- Spacecraft and Cryogenic Technologies
- Electromagnetic Launch and Propulsion Technology
- Spectroscopy and Quantum Chemical Studies
- Particle Accelerators and Free-Electron Lasers
- Electron and X-Ray Spectroscopy Techniques
- Geophysics and Gravity Measurements
- Magnetic and transport properties of perovskites and related materials
- Molecular Junctions and Nanostructures
- Advancements in Semiconductor Devices and Circuit Design
- Atomic and Subatomic Physics Research
- Semiconductor materials and devices
- Gyrotron and Vacuum Electronics Research
- Digital Holography and Microscopy
- Quantum and electron transport phenomena
Lanzhou University
2023-2025
Green Chemistry
2025
Sichuan University
2025
University of California, Los Angeles
1992-2002
University of Wisconsin–Madison
2000
Fusion Academy
1992-1999
Fusion (United States)
1992-1999
Abstract Controlling domain switching and phase transitions in ferroelectric materials under external fields is crucial for advanced device applications. However, the mechanism kinetics governing mechanically induced relaxor Pb(Mg 1/3 Nb 2/3 )O 3 ‐PbTiO remain some unclear understanding, especially variable strain rates. To investigate this, localized mechanical stress applied using nanoindentation to PMN‐PT single crystals. With aid of Raman spectroscopy high‐resolution transmission...
Reduction of core-resonant m=1 magnetic fluctuations and improved confinement in the Madison Symmetric Torus [Dexter et al., Fusion Technol. 19, 131 (1991)] reversed-field pinch have been routinely achieved through control surface poloidal electric field, but it is now known that has limited part by edge-resonant m=0 fluctuations. Now, refined field control, plus toroidal possible to reduce simultaneously This allowed high-energy runaway electrons, possibly indicative flux-surface...
Improved confinement has been achieved in the MST through control of poloidal electric field, but it is now known that improvement limited by bursts an edge-resonant instability. Through refined field control, plus toroidal we have suppressed these bursts. This led to a total beta 15% and reversed-field-pinch-record estimated energy time 10 ms, tenfold increase over standard value which for first substantially exceeds scaling characterized most reversed-field-pinch plasmas.
The multichannel far-infrared (FIR) heterodyne polarimeter-interferometer system on the Madison Symmetric Torus (MST) is now operational. combined consists of 11 channels with variable radial and toroidal spacing. Poloidal magnetic field determined by measuring Faraday rotation FIR laser beam after propagation through plasma use a phase technique. polarimeter has 3 mrad rms noise level 1 ms temporal resolution while interferometer nedl=1×1012 cm−2 time response μs. Absolute calibration...
The origin of large scale density fluctuations and their role in electron transport has been investigated the Madison Symmetric Torus reversed-field pinch [R. N. Dexter et al., Fusion Tech. 19, 131 (1991)]. At medium frequencies (10–30 kHz), ñ is associated with core-resonant magnetic having poloidal mode number m=1 toroidal numbers n=6–10. These chord-averaged are shown to be coherent radial flow fluctuations, permitting fluctuation-induced particle flux form 〈ñṽr〉 studied. In edge,...
A recent study conducted on the Madison Symmetric Torus reversed-field pinch has shown that control of density fluctuations can be achieved through modification current profile. Most power in is directly associated with core-resonant resistive tearing modes. We report that, during auxiliary drive experiments, these are reduced about an order magnitude over entire plasma cross section and resulting electron confinement increased eightfold.
Electron temperature and density fluctuations are measured in the core of Texas Experimental Tokamak-Upgrade (TEXT-U) [P. H. Edmonds, E. R. Solano, A. J. Wootton, Proceedings 15th Symposium on Fusion Technology, Utrecht (Elsevier Science, Amsterdam, 1989), Vol. 1, p. 342] plasma across poloidal cross section. The high spatial resolution heavy-ion beam probe (HIBP) correlation radiometry electron cyclotron emission (CRECE) reveal that both strongly poloidally asymmetric. Temperature...
As a consequence of recent improvements to the far-infrared (FIR) interferometer time response, from bandwidth 10 kHz up 1 MHz, high-frequency density fluctuations can now be resolved on Madison symmetric torus (MST) reversed-field pinch. The phase measurement allows absolute calibration fluctuation amplitude while eleven chords generate information spatial distribution. Density 200 are observed. A unique feature MST is that six toroidally displaced 5° remaining five. Hence, besides poloidal...
A polarimetry capability has been added to the UCLA multichord far-infrared heterodyne interferometer system on TEXT-Upgrade. The polarimeter utilizes a phase technique in order measure Faraday rotation angle of incident laser beam upon transmission through plasma. From these data one derives information poloidal magnetic field, current density and safety factor profiles. response profiles electron cyclotron resonance heating fast ramps is investigated.
A far-infrared polarimeter diagnostic has been added to the UCLA multichord heterodyne interferometer system on TEXT-Upgrade. The utilizes phase technique of Rice [Rev. Sci. Instrum. 63, 5002 (1992)] in order measure Faraday rotation angle incident laser beam upon transmission through plasma. From these data one derives information poloidal magnetic field, current density, and safety factor profiles. Due excellent port access polarimeter/interferometer scanning capability, profile can be...
High-resolution interferometry using far-infrared laser radiation is employed on TEXT-Upgrade to measure the spatial and temporal evolution of electron density profile as well small-scale perturbations. Perturbations induced by naturally occurring sawtooth oscillations or externally imposed gas modulations can be used ascertain local particle flux transport coefficients in plasma interior. Density islands associated with Mirnov activity also resolved, providing detailed information at island...
Experimental results are described from an integrated interferometer-reflectometer system implemented on TEXT-Upgrade. In plasma regions where the systems have spatial overlap, excellent agreement is observed between independently measured electron density profiles. Combined data used to obtain optimal total profile. By removing chords interferometer, one can examine how resolution compromised as channel number decreases and spacing varies. Depending expected profile shapes (i.e. flat or...
A recent study investigating the role of electron density fluctuations in particle transport has been conducted on Madison Symmetric Torus reversed-field pinch. Four diagnostics enabled this experiment: a high-speed multichord far-infrared laser interferometer, Hα array, 64-position magnetic coil and Doppler spectrometer that measured impurity ion flow fluctuations. Correlation analysis is used to elucidate relationship among density, magnetic, We observe are highly coherent with resulting...
The UCLA far-infrared scattering/interferometry system on TEXT-Upgrade has recently been modified to include a two-dimensional capability. Along with the vertically viewing system, horizontal view added. For interferometric measurements of plasma density profile, vertical consists 45 cm array while spans 15 cm. Density profiles for Text-Upgrade plasmas will be presented. collective scattering electron fluctuations, cross correlation scattered signals from two orthogonal views at same wave...
Relaxor ferroelectric single crystals of Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN–PT) have outstanding electromechanical properties in the linear regime. When operated across a phase transition, these are significantly enhanced. Understanding transition mechanism under external fields is crucial for new application PMN–PT that takes advantage this transition. In present study, PMN–0.3PT subjected to mechanical loading/unloading process and effects electric field on responses crystal coupled...