A5100380191- Magnetic confinement fusion research
- Laser-Plasma Interactions and Diagnostics
- Ionosphere and magnetosphere dynamics
- Plasma Diagnostics and Applications
- Laser-induced spectroscopy and plasma
- Astro and Planetary Science
- Particle accelerators and beam dynamics
- Planetary Science and Exploration
- Dust and Plasma Wave Phenomena
- Superconducting Materials and Applications
- Space Exploration and Technology
- Nuclear Physics and Applications
- Optical Systems and Laser Technology
- Solar and Space Plasma Dynamics
- Fluid Dynamics and Turbulent Flows
- Engineering Applied Research
ENN (China)
2021-2024
Technische Universität Ilmenau
2018
Abstract As a new spherical tokamak designed to simplify the engineering requirements of possible future fusion power source, EXL-50 experiment features low aspect ratio vacuum vessel (VV), encircling central post assembly containing toroidal field coil conductors without solenoid. Multiple electron cyclotron resonance heating (ECRH) resonances are located within VV improve current drive effectiveness. Copious energetic electrons produced and measured with hard x-ray detectors, carry bulk...
XuanLong-50 (EXL-50) is the first medium-size spherical torus (ST) in China, with toroidal field at major radius 50 cm around 0.5T. CS-free and non-inductive current drive via electron cyclotron resonance heating (ECRH) was main physics research issue for EXL-50. Discharges plasma currents of kA - 180 were routinely obtained EXL-50, flattop sustained up to or beyond 2 s. The effectiveness on EXL-50 as high 1 A/W low-density discharges using 28GHz ECRH alone power less than 200 kW. reached...
Three-dimensional turbulent magnetoconvection at a Rayleigh number of $Ra=10^7$ in liquid gallium Prandtl $Pr=0.025$ is studied closed square cell for very strong external vertical magnetic fields $B_0$ direct numerical simulations which apply the quasistatic approximation. As or equivalently Hartmann $Ha$ are increased, convection flow that highly absence crosses Chandrasekhar linear stability limit thermal ceased an infinitely extended layer and can be assigned with critical $Ha_{\rm c}$....
A non-relativistic multi-fluid plasma axisymmetric equilibrium model [A. Ishida et al., "Three-fluid and application to spherical torus plasmas sustained by RF electron heating," Plasma Fusion Res. 10, 1403084 (2015)] was developed recently account for the presence of an energetic fluid in addition thermal ion fluids. The formulation a with relativistic electrons is reported this paper. Relativistic effects approximation can appear two ways: due large macroscopic velocity comparable speed...
Abstract Significant number of confined energetic electrons have been observed outside the LCFS (last-closed flux surface) EXL-50’s solenoid-free electron cyclotron resonance heating (ECRH) sustained plasmas. Several measurement technologies applied to verify key characteristics for first time. Experiments reveal that presence high-temperature, low-density can carry relatively large quantities stored energy. The boundary between thermal plasma and fluid is clearly separated distance two...
Abstract Although experiments have demonstrated a feasibility of the electron-cyclotron-wave (ECW) non-inductive current start-up, physical mechanism start-up remains unclear, particularly role preferential confinement collisionless tail electron currents ( <?CDATA ${j_{{\text{TPC}}}}{\text{)}}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>j</mml:mi> <mml:mtext>TPC</mml:mtext> </mml:mrow> </mml:msub> <mml:mtext>)</mml:mtext>...
This study presents novel findings on stochastic electron heating via a random cyclotron wave (ECW) in spherical tokamak. Hard x ray measurements demonstrate the time evolution of hard counts at different energy bands, consistent with predictions from model. The ECW rate shows positive correlation applied power, confirming effectiveness heating. Remarkably, ECW-driven plasma current remains insensitive to incidence angle, model predictions. observed electrons offers potential for exploring...
Abstract As a new spherical tokamak (ST) designed to simplify engineering requirements of possible future fusion power source, the EXL-50 experiment features low aspect ratio (A) vacuum vessel (VV), encircling central post assembly containing toroidal field coil conductors. Multiple electron cyclotron resonance heating (ECRH) resonances are located within VV possibly improve current drive effectiveness. The energetic electrons observed via hard X-ray detectors, carry bulk plasma ranging from...
Abstract In EXL-50 plasma currents over 100 kA are non-inductively generated and maintained solely by electron cyclotron heating (ECH) power with an efficiency of ∼1 A W −1 . These carried energetic electrons (EEs) in the energy range from several tens keV up to hundreds which also account for almost all pressure plasma. This EE component can be viewed as a large number collection various periodic orbits particles. Based on this picture we have developed method particle orbit description...
Abstract A three-fluid equilibrium plasma with bulk and energetic electrons has been observed on the Xuanlong-50 (EXL-50) spherical torus, where play a crucial role in sustaining current pressure. In this study, of multi-fluid was investigated by analyzing relationship between external vertical magnetic field ( B V ), I p poloidal ratio β ) Shafranov formula. Remarkably, our research demonstrates some validity formula presence EXL-50 torus. This finding holds significant importance for...
This study presents observations of coherent modes (CMs) in a spherical tokamak using microwave interferometer near the midplane. The CMs within 30–60 kHz frequency range were observed during electron cyclotron resonance heating only, and increased proportionally with square root temperature $R = 0.7m$ . Generally, these displayed bursting chirping signatures strong density rise fall. Their appearance indicated an increase intensity hard x rays, suggesting deterioration energetic...
Abstract The fully non-inductive spherical tokamak EXL-50, built and operated by the ENN private limited company, has routinely achieved high current drive efficiency of ∼ 1 A/W in only ECRH powered experiments. We have numerically investigated effectiveness multiple electron cyclotron resonance (ECR) harmonics generating such a (ECCD) plasma start-up. Fokker-Planck equation is solved to obtain distribution function, under steady state relativistic nonlinear Coulomb collision quasi-linear...