A5101791816- Gyrotron and Vacuum Electronics Research
- Magnetic confinement fusion research
- Adaptive optics and wavefront sensing
- Particle accelerators and beam dynamics
- Optical measurement and interference techniques
- Pulsed Power Technology Applications
- Laser-Plasma Interactions and Diagnostics
- Tropical and Extratropical Cyclones Research
- Solar and Space Plasma Dynamics
- Advanced X-ray Imaging Techniques
- Climate variability and models
- Meteorological Phenomena and Simulations
- Optical Systems and Laser Technology
- Advanced Thermodynamics and Statistical Mechanics
- Photonic and Optical Devices
- Advanced Optical Imaging Technologies
- Ionosphere and magnetosphere dynamics
- Advanced optical system design
- Geophysics and Gravity Measurements
- Advanced Image Processing Techniques
- Urban Heat Island Mitigation
- Advanced Image Fusion Techniques
- Oceanographic and Atmospheric Processes
- Superconducting Materials and Applications
- Optical Coatings and Gratings
NSF National Center for Atmospheric Research
2024
U.S. National Science Foundation
2024
Huazhong University of Science and Technology
2015-2019
China Astronaut Research and Training Center
2014-2016
China XD Group (China)
2014
National University of Defense Technology
2009-2012
To enhance parameters of the plasma and improve magnetic confinement performance, a 105-GHz electron cyclotron resonance heating (ECRH) system is being built on J-TEXT. We designed quasi-optical launcher which mainly consists focusing mirror steering mirror. The optimized by considering localized deposition, close to boundary for flexible adjustment toroidal poloidal injection angles wave. rotation are independently controlled mechanical structure. For our design, beam radius at center...
Abstract The linear condition, spatial resolution and filter model of a curvature sensor are obtained by brief intelligible frequency analysis approach. bounded interval propagation distance is given considering the condition noise in intensity measurement. effects nonlinearity measurement on different aberrations discussed. We provide guide to choose sensor. should be large for low-frequency aberrations, which greatly affected noise, small high-frequency limited nonlinear effect. For...
Phase retrieval on an annular pupil and sector by using the eigenfunction method to solve transport of intensity equation is proposed. The analytic expressions Laplacian eigenfunctions with Neumann boundary condition are given. phase can be expanded as a set corresponding pupil, coefficients obtained integral derivative along optical axis. simulated, accurate retrieved results obtained.
To make the J-TEXT tokamak more flexible for physics experiments, an electron cyclotron resonance heating (ECRH) system is being developed. The main parts of ECRH are donated by Culham Science Center from former COMPASS-D, including six 60 GHz/200 kW/5 s (0.5 s) gyrotrons, magnets, and auxiliary power supplies transmission parts, so on. For system, output mode gyrotron Varian Associates, Inc. TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...
We introduce a modal wave front sensing technique of using binary computer generated hologram (BCGH) and coding approach. Several types Zernike aberrations were encoded into the BCGH this method. Light was modulated by single aberration mode respectively, holographic wavefront sensor simulated verified. The results show that, distorted special mode, after BCGH, can be transformed beams which have relative intensity, reflect change trend coefficients in unknown wavefront.
The dynamical theory of mass and momentum transport by organized convection, produced Moncrieff, is extended using a hydrodynamical model, two-dimensional buoyant quasi-three-dimensional model. Each characterized three relative flow branches that idealize the structure squall-line cloud systems. Despite physical structural diversity, clear similarity in transports holds for entire hierarchy, such as negative-dominant flux systems propagating positive x-direction. Shear buoyancy are shown to...
Electron cyclotron resonance heating (ECRH) is an important auxiliary method which widely used in magnetic confinement fusion. For the ECRH system on J-TEXT, signals should be transmitted to control for monitoring and protection also data acquisition system. Considering high-voltage harsh electromagnetic interference environment, reliable fiber-optic transmission links are applied. Transmitted by modules, response time of digital can less than 1 μs. According requirements, two practical...
For high-power millimeter systems, reflective gratings (RGs) are usually used to control the wave polarization. This paper presents polarization strategy with two identical RGs. We use coordinate transformation method for RG design. A code based on this is checked by numerical examples and also low-power experiments. Experiments carried out at frequencies of 60, 70, 105 GHz. Four manufactured test. present compare calculated results integral test results. The comparison indicate that...
With betatron oscillation characteristics of the electron beam and ion channel effect taken into account, dispersion electrostatic modes TM for a relativistic guided by are studied. Dispersion relations derived solved numerically to investigate dependence on frequency ratio radius waveguide radius. The effects boundary current characteristic interaction between analyzed. When considering current, strong channel, new low-frequency branch arises TM01 is increased with same parameters.
Adaptive optics (AO) in conjunction with subsequent postprocessing techniques have obviously improved the resolution of turbulence-degraded images ground-based astronomical observations or artificial space objects detection and identification. However, important tasks involved AO image postprocessing, such as frame selection, stopping iterative deconvolution, algorithm comparison, commonly need manual intervention cannot be performed automatically due to a lack widely agreed on quality...
As a flexible and controllable auxiliary heating method, electron cyclotron resonance current drive has been widely used in various plasma confinement devices also will be on J-TEXT. The main parts of the J-TEXT systems under development are donated by Culham Science Center, including six 60 GHz/200 kW/5 s (0.5 s) gyrotrons, magnets power supplies for gyrtrons, transmission parts, etc. For these systems, output mode gyrotron is TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...
An electron cyclotron (EC) resonance heating (ECRH) system with four 60-GHz/200-kW/0.5-s gyrotrons donated by the Culham Science Center is being developed on J-TEXT for plasma and magnetohydrodynamics studies. A controlled polarization launcher has been designed to inject EC beam into desired direction. The polarizer sinusoidal grooves integrated control of wave. We use coordinate transformation method design. parameters polarizer, including rotation angle ellipticity, are measured a...
Atmospheric turbulence-induced wavefront deformation can be only partially corrected by adaptive optics (AO) techniques in astronomical or artificial space object imaging; an accurate estimation of the residual-wavefront phase is still needed to approach diffraction-limited resolution. The discrete gradients measured Shack-Hartmann sensors (SHWFS) help with estimation. In this study, we build a dynamic average slopes measurement model for SHWFS short-exposure AO images postprocessing;...
Taking self-fields into consideration, dispersion properties of two types electromagnetic modes for a high energy electron beam guided with an ion channel are investigated by using the linear perturbation theory. The dependences frequencies waves on radius, betatron frequency and boundary current revealed. It is found that radius have different influences behavior compared previous works. As taken account, TM will branches low-frequency branch emerged as new in strong case. This has similar...
This paper presents the application of reflective gratings as polarizers for electron cyclotron heating system in magnetic confinement fusion fields. Two methods, integral method and coordinate transformation method, are introduced grating design. Codes based on two methods developed. Numerical results agree well with each other, indicating that codes available. Additionally, a is designed, manufactured tested. The also coincide calculation results.