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An electron Penning-Malmberg trap,which can confine an electron column and provide a good platform to investigate the cross-filed transportation of strongly magnetized electron plasma ,has been set up.With the device,an electron plasma with a density of 10^7 cm^-3 can be confined for a relatively long time.The structure of the trap,electron source,as well as the way how th measure electron plasma density profile and velocity distrbustion are introduced in detail. 相似文献
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A front-end optics system has been developed for the EAST microwave imaging reflectometry for 2D density fluctuation measurement.Via the transmitter optics system,a combination of eight transmitter beams with independent frequencies is employed to illuminate wide poloidal regions on eight distinct cutoff layers.The receiver optics collect the reflected wavefront and project them onto the vertical detector array with 12 antennas.Utilizing optimized Field Curvature adjustment lenses in the receiver optics,the front-end optics system provides a flexible and perfect matching between the image plane and a specified cutoff layer in the plasma,which ensures the correct data interpretation of density fluctuation measurement. 相似文献
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冯喜 刘阿娣 周楚 邹晓岚 庄革 王守信 王明远 刘海庆 丁卫星 张寿彪 吴木泉 朱翔 郝保龙 张津 刘朝阳 季佳旭 仲小明 刘深 谢锦林 林晓东 黄建军 高翔 万元熙 《等离子体科学和技术》2023,(11):63-73
To interpret the common symmetric peaks caused by the large-scale structure in the complex S(f) spectrum from the heterodyne Doppler reflectometry(DR) measurement in EAST, a 2D circular-shaped O-mode full-wave model based on the finite-difference time-domain method is built. The scattering characteristics and the influences on the DR signal from various scales are investigated. When the structure is located around the cutoff layer, a moving radial or poloidal large-scale structure kθ■... 相似文献
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Propagation of whistler-mode waves in a magnetized plasma structure is investigated in the Keda linear magnetized plasma device. The magnetized plasma structure has its density peak in the center, and the background magnetic field is homogeneous along the axial direction. A whistlermode wave with a frequency of 0.3 times of electron cyclotron frequency( fce) is launched into the plasma structure. The wave normal angle(WNA) is about 25°, and the wavefront exhibits a wedge structure. During propag... 相似文献
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1.IntroductionPenningtrapshavebeenwidelyusedtotrapchargedparticles,suchaselectronsorions,forstudyonthefundamentalpropertiesofparticles,andthetransportandequilibriumpropertiesofnon--neutralplasmas[1-4].InaPenningtrap,auniformaxialmagneticfieldprovidesradialconfinement,whiletheelectricfieldbetweentheelectrodesprovidesaxialone.Thetrapcanconfineasmallnumberofchargedparticlesforverylongtime.However,becauseoftheself-electricfieldeffect,themaximumdensityofnonneutralplasma(electron)radicallyconfinedb… 相似文献
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In this article we present ideas of providing appropriate poloidal magnetic field for helimaks to help to generate toroidal magnetic plasma torus.Placing a conductive ring in the center of the cross-section to induce a suitable current,we change the helical magnetic field lines in the helimak discharge into magnetic surface.In this kind of discharge,the plasma density is greatly increased,and the corresponding density fluctuation is significantly decreased,showing a better confinement by magnetic shear.It allows more flexible and efficient experimental investigations on the toroidal magnetic confinement plasmas to be carried on in this kind of device. 相似文献
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An extraordinary-mode(X-mode) frequency-modulated continuous-wave(FMCW) profile reflectometer has been built on EAST.In the reflectometer,continuous waves with frequency sweeping from 12.5 GHz to 18 GHz were generated through a Hyperabrupt Tuned-varactor Oscillator(HTO) source and a four times active multiplier was used to increase the frequency to V-band(50 GHz to 72 GHz).The polarization of horn lens antenna is perpendicular to the magnetic field line at the edge plasmas.According to the V-band frequency range and polarization,the system cover density range from 0.5 × 1019m 3to 3.0 × 1019m 3(when toroidal magnetic field is 1.8 T),with time resolution of 12.5 ~ 50 μs.The density profile could be calculated by assuming the edge profile through an empirical equation.The maximum spatial error deduced by the method is about 4 cm.This reflectometer has been successfully applied in 2010 autumn EAST campaign,the temporal evolution of density profiles was acquired during the low confinement mode to high confinement mode transition.The density pedestal of EAST Tokamak was observed and the top value and gradient of the density pedestal were estimated. 相似文献
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The Doppler reflectometer(DR), a powerful diagnostic for the plasma perpendicular velocity(u⊥) and turbulence measurement, has been widely used in various fusion devices. Many efforts have been put into extracting the Doppler shift from the DR signal. There are several commonly used methods for Doppler shift extraction, such as the phase derivative, the center of gravity, and symmetric fitting(SFIT). However, the strong zero-order reflection component around 0 k Hz may interfere with the calcula... 相似文献