共查询到20条相似文献,搜索用时 0 毫秒
1.
V. I. Gavrilenko A. L. Korotkov Z. F. Krasil'nik V. V. Nikonorov 《Optical and Quantum Electronics》1991,23(2):S163-S176
A survey of techniques and experimental results from the investigation of hot hole effects in germaniumvia their absorption and spontaneous emission in the far IR (FIR) range. The results of a cyclotron resonance absorption investigation of hot holes in crossedE andB fields in a wide wavelength range 0.3 to 2 mm at 40 K are presented. The light hole sub-band overpopulation and the absorption pecularities under streaming conditions are investigated. Mechanisms of FIR emission ofp-Ge at liquid helium temperatures are analysed. A new emission mechanism associated with the crystal lattice emission is revealed and an estimation of FIR phonon-assisted absorption is made. The population inversion of h-l transitions is diagnosed by the effect of flare up of FIR luminescence of hot holes in Ge with an applied magnetic fieldB E, and the FIR radiation gain at l-h transitions is estimated. The different factors affecting the flare up and the gain of FIR radiation, such as the crystallographic orientation of the crossedE andB fields, slight nonorthogonality of theE andB fields, the sample heating during the electric field pulse and the uniaxial stress, are discussed. 相似文献
2.
Τ ά��������������� 《核聚变与等离子体物理》2018,38(2):144-151
为了给EAST 电子回旋共振加热物理实验提供理论依据和模拟预测,从电子热输运方程出发,运用 CRONOS 输运程序对不同等离子体和波参数下,电子回旋加热效果进行了数值模拟计算。给出不同电子回旋波功率、入射角、电子密度和纵场等参数对电子回旋加热效果的影响,预测在不同参数下,电子温度、等离子体总内能和能量约束时间的变化,分析了其原因,并与实验结果进行了初步的比较。 相似文献
3.
电子回旋共振(ECR)中和器是微型ECR离子推力器的重要组成部分,其引出的电子用于中和ECR离子源的离子束流,避免了航天器表面电荷堆积,并且电子引出性能对推力器的整体性能起着重要作用.为了分析影响微型ECR中和器电子引出的因素,本文建立了二维轴对称PIC/MCC计算模型,通过数值模拟研究不同磁路结构对中和器的电子引出,及不同腔体长度对壁面电流损失的影响.计算结果表明, ECR区位置和引出孔附近磁场构型对中和器的电子引出性能至关重要.当ECR区位于天线上游,电子在迁移扩散中易损失,并且电子跨过引出孔前电势阱所需的能量更高.如果更多磁力线平行通过引出孔,中和器引出相同电子电流所需电压较小.当ECR区被天线切割或位于下游时,电子更易沿磁力线迁移到引出孔附近,从而降低了收集板电压.研究了同一磁路结构下不同腔体长度对电子引出的影响,发现增加腔体长度,使得更多平行轴线的磁力线通过引出孔从而避免电子损失在引出板表面,增加了引出电子电流.研究结果有助于设计合理的中和器磁路和腔体尺寸. 相似文献
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为了打破二维模拟回旋脉塞的一些局限性,研究了电子回旋受激辐射的基本原理,使用唯象的描述方法,以统计物理学为基础,在电子回旋中心坐标系中完成了三维Yee网格模型中对电子注平衡态物理模型的数值建模,并结合PIC方法和FDTD算法进行电子回旋脉塞的数值模拟.为了减少计算时间,在模拟中加入了MPI并行算法,加速比能提高到2.7以上.最后以一个94 GHz的回旋振荡管为例,对它的整体结构进行了模拟,并通过对频谱,功率,工作模式等方面验证了模拟的正确性.
关键词:
电子回旋脉塞
Yee网格模型
PIC方法
FDTD算法 相似文献
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基于漂移扩散近似,在轴对称假设下,对电子回旋共振等离子体源腔室内的等离子体建立了二维流体模型.采用有限差分法对所建立的模型进行了自洽数值模拟,得到了等离子体密度均匀性随时间演化的数值结果.通过对数值结果的分析,研究了背景气体压强、微波功率和磁场线圈电流对等离子体密度均匀性的影响.研究表明,在电离初期,电子密度的均匀性好于离子密度的均匀性.在电离后期,离子密度的均匀性好于电子密度的均匀性.随着背景气体压强的增大,电子密度和离子密度的均匀性都在增加,且离子密度的均匀性增加的更快.随着微波功率的增大,电子密度和
关键词:
等离子体密度均匀性
背景气体压强
微波功率
磁场线圈电流 相似文献
8.
Electron cyclotron current drive (ECCD) will be applied in the EAST tokamak during its the new campaign. In order to provide theoretical predictions for relevant physical experiments, some numerical simulations of ECCD with the parameters of EAST have been can'ied out by using TORAY-GA code based on the understanding of ECCD mechanisms. ECCD efficiencies achieved in different plasma and electron cyclotron (EC) wave parameters are given. The dependences of ECCD characteristics on EC wave injection angle, toroidal magnetic field, plasma density, and temperature are presented and discussed. 相似文献
9.
E. V. Samsonov B. N. Gikal O. N. Borisov I. A. Ivanenko 《Physics of Particles and Nuclei Letters》2014,11(2):158-168
In Flerov’s Laboratory of Nuclear Reactions of JINR in the framework of project “Beta” a cyclotron complex for a wide range of applied research in nanotechnology (track membranes, surface modification, etc.) is created. The complex includes a dedicated heavy-ion cyclotron DC-110, which yields intense beams of accelerated ions Ar, Kr and Xe with a fixed energy of 2.5 MeV/A. The cyclotron is equipped with external injection on the base of ECR ion source, a spiral inflector and the system of ions extraction consisting of an electrostatic deflector and a passive magnetic channel. The results of calculations of the beam dynamics in measured magnetic field from the exit of spiral inflector to correcting magnet located outside the accelerator vacuum chamber are presented. It is shown that the design parameters of ion beams at the entrance of correcting magnet will be obtained using false channel, which is a copy of the passive channel, located on the opposite side of the magnetic system. Extraction efficiency of ions will reach 75%. 相似文献
10.
采用粒子模拟与蒙特卡罗相结合(PIC/MCC)的方法,应用电磁模型,编写了准三维的电子回旋共振(ECR)放电电离过程的模拟程序,得到了ECR放电过程中电子与离子的相空间分布、电磁场分布.通过对这些分布随时间演化的分析,得出ECR加热发生在ω≈ωc0且垂直于轴向的区域;ECR区域,微波能量几乎全部耦合给电子,获得能量的电子通过与中性粒子的电离碰撞产生了大量的带电粒子;随着放电的进行,大量带电粒子通过频繁的碰撞,分布由各向异性逐渐趋于各向同性.
关键词:
电子回旋共振放电
粒子模拟
蒙特卡罗
电离 相似文献
11.
L. E. Vorobjev S. N. Danilov D. V. Donetsky D. A. Firsov Yu. V. Kochegarov V. I. Stafeev 《Optical and Quantum Electronics》1993,25(10):705-721
A narrowband far-infrared laser on intersubband transitions of hot holes was constructed and investigated. Two methods were used: mode selection due to intercavity Fabry-Perot resonator and selection of a narrow spectral lasing region by special multilayer mirror. The emission spectra of the laser were determined. The radiation bandwidth measured was 0.2 cm-1 as compared with 15–30 cm-1 for nonselective resonator. Lasing with selective resonator could occur at any two wavelengths in the ranges 80–120 and 150–200 m. The wavelength was modified by altering electric and magnetic fields. The radiation power was about 10 W and of the same kind as that of a laser without a mode selector. The narrowband laser was used in investigation of CR of electrons in n-InSb. 相似文献
12.
V. N. Komarov 《Technical Physics》2001,46(6):718-722
The motion of a charged particle under the combined action of a magnetostatic field and a circularly polarized electromagnetic wave of phase velocity u higher than c, the wave being aligned with the field, is studied theoretically. A nonlinear resonance curve is found. Certain integrals of motion are derived. 相似文献
13.
Physical principles, design and operation characteristics of a negative mass cyclotron resonance maser inp-type germanium are considered in this paper. The formation of anisotropic inverted distributions of negative effective mass heavy holes in strong electric and magnetic fieldsE H [001], resulting in negative conductivity in the millimetre and submillimetre wavelength ranges, is discussed. The generation is observed at 0.9 to 8mm in low compensated germanium samples with the hole concentration rangeN
0 2×1012 to 2×1014 cm–3 at low temperaturesT 25 K in electric fieldsE 40 to 350Vcm–1. The maser frequency is tuned by the magnetic field corresponding to a cyclotron resonance frequency of carriers with an effective mass ofm
c 0.4m
0. The spectral width of the emission in single mode operation does not exceed several megahertz. A pulse duration of 1 to 200 s and a repetition rate off
rep 1 to 200 Hz has been obtained limited by sample heating. Possibilities of improving the maser characteristics inp-Ge as well as in other AIII Bv semiconductors and the perspectives of new frequency tuning methods due to the application of uniaxial stress and magnetic field are demonstrated. 相似文献
14.
We have studied cyclotron resonance of electrons in an inversion layer on the surface of p-type InSb. With increasing surface charge density ns a number of distinct resonance peaks are found to appear. These are attributed to cyclotron resonance in different electric subbands. The various cyclotron masses are found to increase with ns and with the frequency of the far-infrared laser source. 相似文献
15.
We consider the cyclotron resonance in a semiconductor which has a band with a relativistic energy-momentum dispersion and show that, when subject to quasi-resonant radiation, the energy of a free carrier in this band and the relative potential drop between the two surfaces of the semiconductor facing the radiation exhibit bistability under classical single electron approximation. 相似文献
16.
The optical absorption coefficient of free polarons in a magnetic field is calculated for weak coupling at zero temperature in the E//H configuration. Characteristic fluctuations in the absorption are reported. 相似文献
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Cyclotron resonance has been performed on the conduction band of germanium using a cyanide laser at 891 GHz and a superconducting magnet of up to 110 kG. This is 2.5 times higher in frequency and 10 times higher in field than previous cyclotron resonance measurements reported for n-Ge. The effective masses do not change from their calues at lower frequencies and fields, but the scattering frequencies are 1.5 to 5 times larger. A new scattering mechansm is suggested to explain the increased scattering. 相似文献
19.
Meyyappan R. Govindan T.R. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1995,23(4):623-627
A simple model to predict the spatially-averaged plasma characteristics of electron cyclotron resonance (ECR) reactors is presented. The model consists of global conservation equations for species concentration, electron density and energy. A gas energy balance is used to predict the neutral temperature self-consistently. The model is demonstrated for an ECR argon discharge. The predicted behavior of the discharge as a function of system variables agrees well with experimental observations 相似文献
20.
电子回旋共振离子推力器(electron cyclotron resonance ion thruster,ECRIT)离子源内等离子体分布会影响束流引出,而磁场结构决定的ECR区与天线的相对位置共同影响了等离子体分布.在鞘层作用下,等离子体中的离子或电子被加速对壁面产生溅射,形成壁面离子或电子电流,造成壁面磨损和等离子体损失,因此研究壁面电流与等离子体特征十分重要.为此本文建立2 cm ECRIT的粒子PIC/MCC(particle-in-cell with Monte Carlo collision)仿真模型,数值模拟研究磁场结构对离子源内等离子体与壁面电流特性的影响.计算表明,当ECR区位于天线上游时,等离子体集中在天线上游和内外磁环间,栅极前离子密度最低,故离子源引出束流、磁环端面电流和天线壁面电流较低.ECR区位于天线下游时,天线和栅极上游附近的等离子体密度较高,故离子源引出束流、天线壁面电流和磁环端面电流较高.腔体壁面等离子体分布与电流受磁场影响最小. 相似文献