共查询到20条相似文献，搜索用时 15 毫秒
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对原有的低混杂波电流驱动模拟程序进行改进,使之能够研究EAST上如何控制低混杂波功率沉积和电流驱动分布.在EAST非圆截面的平衡位形下,应用改进后的程序详细计算不同低混杂波功率谱、等离子体密度和温度分布对低混杂波功率沉积位置和电流驱动剖面分布的影响.通过计算发现,选取合适的低混杂波功率谱,等离子体温度分布和密度分布可以对功率沉积位置和电流驱动分布的剖面进行控制;调节等离子体温度分布可以很好的控制低混杂波近轴电流驱动分布和离轴电流驱动分布. 相似文献
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Nonlinear structures of lower hybrid wave in collision plasmas are studied using the two-fluid theory.The oscillatory shock wave is observed due to the effects of the electron-neutral collision and the density inhomogeneity.In the cold electron limit,the oscillatory shock wave becomes the ordinary shock wave.In the collisionless limit,the dominated equation becomes Kd V equation and the lower hybrid solitons arise.The amplitude of the nonlinear structure is depressed by the plasma inhomogeneity,but is hardly affected by the electron-neutral collision. 相似文献
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螺旋波等离子体增强化学气相沉积氮化硅薄膜 总被引：7，自引：1，他引：7
利用螺旋波等离子体增强化学气相沉积(HWP-CVD)技术,以SiH4和N2为反应气体进行了氮化硅(SiN)薄膜沉积,并研究了实验参量对薄膜特性的影响.利用傅里叶变换红外光谱、紫外—可见光谱和椭偏光检测等技术对薄膜的结构、厚度和折射率等参量进行了测量.结果表明,采用HWP-CVD技术能在低衬底温度条件下以较高的沉积速率制备低H含量的SiN薄膜,所沉积的薄膜主要表现为Si—N键合结构.采用较低的反应气体压强将提高薄膜沉积速率,并使薄膜的致密性增加.适当提高N2/SiH4比例有利于薄膜中H含量的降低.关键词：螺旋波等离子体化学气相沉积氮化硅薄膜 相似文献
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HT-7 Tokamak拥有离子回旋波(ICRF)和低杂波(LHW)两套加热系统.ICRF主要对加热离子有比较好的加热效果,LHW则主要是通过电子Landau阻尼加热电子.除此之外,在ICRF和LHW协同加热的条件下,可以对等离子体产生更有效的加热效果,增加等离子体的聚变反应截面,增加聚变中子产额.本文报道了LHW对改善ICRF和等离子体耦合的重要作用,ICRF和LHW加热等离子体中电子温度随时间的演化过程,计算了放电过程中电子逃逸的阈值能量,分析了逃逸电子的产生过程,以及放电过程中的中子产额.研究结果发 相似文献
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螺旋波等离子体化学气相沉积纳米硅薄膜的光学发射谱研究 总被引：4，自引：0，他引：4
利用光学发射谱技术对螺旋波等离子体化学气相沉积纳米硅薄膜的等离子体内活性粒子的光发射特征进行了原位测量.研究了薄膜沉积过程中各实验参量对活性基团SiH*, Hβ以及Hα的发射谱强度的影响.实验结果表明,静态磁场的加入可显著提高反应气体 的解离效率 ;适当的氢稀释可以提高氢活性粒子的浓度,而过高的氢稀释比将使含硅活性基团浓度显著 减小;提高射频馈入功率整体上可以使各活性粒子的浓度增加,并有利于提高到达衬底表面 氢活性粒子的相对比例.结合螺旋波等离子体色散关系和等离子体特点对以上结果进行了分 析.该结果为螺旋波等离子体沉积纳米硅薄膜过程的理解及制备工艺参数的调整提供了基础 数据.关键词：光学发射谱螺旋波等离子体化学气相沉积纳米硅薄膜 相似文献
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应用作者最新改进的求解FOKKER-PLANK方程的程序,首次得到了低杂波电流驱动下的加热功率密度和加热功率.这些数值模拟结果不仅很好地解决了低杂波电流驱动中的功率平衡问题,而且也能为以后的托卡马克低杂波电流驱动实验提供一定的指导作用. 相似文献
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用有限拉莫尔半径(FLR)修正的相对论色散关系进行了数值模拟，研究了电子回旋波在高温、高密等离子体的功率沉积，并将计算结果与应用弱相对论Fokker-Planck方程得到的结果进行了比较。结果表明，在高温、高密等离子体中，波功率的吸收非常集中；平行折射率、极向发射位置和发射波频率的变化都会影响波功率沉积的大小和分布；平行折射率变大后，FLR效应会使波的阻尼减少。 相似文献
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A program is developed to calculate the ion energy distributions （IEDs） of Ar2^＋ making use of a simplified kinetic model with a combination of Monte Carlo method. Several coefficients are used to realize good match between the calculated and measured results. Some important assumptions are confirmed： argon excimer ions have short lifetime, hence they are formed in a short range before the collecting electrode. The excimer ions that encounter collisions will be discarded because they turn to other ion species after they collide with argon atoms. From the calculated results some plasma parameters such as the cross section or neutral density in discharge could be evaluated. 相似文献
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The modulation of absorption manner in helicon discharge by changing the profile of low axial magnetic field is explored experimentally in this work. The experiments are carried out in Boswell-type antenna driven by 13.56-MHz power source in 0.35-Pa argon environment. The peak of the external non-uniform magnetic field(B_(ex)) along the axis is observed in a range from 0 Gs to 250 Gs(1 Gs = 10~(-4) T), where the electron density varies from 0.5×10~(16) m~(-3) to 9×10~(16) m~(-3).When Bex is located near the tube upper end sealed by a dielectric plate, or near the tube bottom end connected with a diffusion chamber, the plasmas are centralized in the tube in the former case while the strong luminance appears between the edge of the tube and the axial line in the latter case. When Bex is located in the middle of the antenna, moreover, an effective resistance(R_(eff)) peak appears apparently with increasing magnetic field. The glow moves toward first the edge of the tube and then the two antenna legs as the magnetic field increases. The discharge in this case is caused by the absorption of Trivelpiece–Gould(TG) wave. It is suggested that B_(ex) is located in the middle of the antenna to obtain a higher efficiency of power transfer. 相似文献
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Features of the two thin-film techniques, atomic layer deposition (ALD) and molecular layer deposition (MLD), are combined to build up a stable novel inorganic-organic hybrid material of the (-Ti-N-C6H4-O-C6H4-N-)n type, deposited from successive pulses of TiCl4 and 4,4′-oxydianiline precursors. Depositions in the temperature range of 160-230 °C resulted in unstable films, while the films obtained in the temperature range of 250-490 °C were found stable in atmospheric air. The growth rate increased with increasing temperature, from 0.3 Å per cycle at 160 °C to 1.1 Å per cycle at 490 °C. 相似文献
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平板型感应耦合等离子体源的线圈配置对功率耦合效率的影响 总被引：1，自引：0，他引：1
基于感应耦合等离子体的变压器模型,分析了感应耦合等离子体的功率耦合效率与线圈配置(几何尺寸、电学参量)及等离子体基本参量(等离子体电子密度、电子-中性粒子有效碰撞频率)之间的关系;然后,改变平板型线圈的匝数从而改变了线圈的几何尺寸、电学参量,并且测量出了不同的线圈所对应的功率耦合效率.实验结果表明,线圈的电感量是能否实现放电的决定性因素;而功率耦合效率则与感应线圈的Q值、放电参量(气压、功率)等密切相关,射频输入功率的增加、放电气压的上升都会导致感应耦合等离子体耦合效率的提高,这与感应耦合等离子体的变压器模型预测结果是符合的. 然而,变压器模型给出的提高线圈Q值可导致耦合效率增强的预测结果仅适用于同等电感量的线圈条件. 本文对于单线圈的感应耦合等离子体源的研究为线圈的优化设计甚至大面积的多线圈感应耦合等离子体源研制提供了理论依据. 关键词：感应耦合等离子体功率耦合效率变压器模型 相似文献
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Yu.V. Arkhipov A. Askaruly D.Yu. Dubovtsev L.T. Erimbetova I.M. Tkachenko 《等离子体物理论文集》2015,55(5):373-380
The dense plasma dynamic collision frequency is modeled by the first two terms of its asymptotic expansion at high frequencies and its values at a few interpolation points on the real axis. This makes the dynamic collision frequency a non‐rational function whose extension onto the upper half‐plane of the complex frequency is holomorphic with a non‐negative imaginary part and with a continuous extension to the real axis. The validity of the suggested analytic form of the latter is tested against the simulation data, where the Kelbg effective potential was used. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Taotao Zhou 《中国物理 B》2022,31(9):95201-095201
The lower hybrid current drive is a potential candidate for sustaining plasma current in tokamak steady-state operations, which could be used in China Fusion Engineering Test Reactor (CFETR) with input power up to a few tens of megawatts. Such high input power could trigger the well-known parametric instabilities (PIs) at the plasma edge affecting the propagation and absorption of the lower hybrid pump waves. By analytically solving the nonlinear dispersion relation describing PIs, an explicit expression of the PI growth rate is obtained and analyzed in detail. It is found that pressure is the key parameter determining the PI characteristics. Ion sound quasi-mode is the dominant decay channel in the low-pressure regime, while the ion cyclotron quasi-mode (ICQM), as well as its harmonics, becomes dominant in the intermediate regime. In the high-pressure regime, only one mixed channel is found, which is related to Landau damping by free-streaming ions. Analytical expressions of growth rates of these decay channels are also obtained to show the parameter dependence at different pressure limits. The above analytical results are used to estimate the PIs on a typical profile of CFETR, and verified by corresponding numerical calculations. ICQM is found to be the strongest decay channel with a considerable growth rate for CFETR. 相似文献
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利用低杂波改善约束的实验研究 总被引：1，自引：0，他引：1
介绍了在HT-6M托卡马克上,利用双低杂波的组合,成功地实现了准稳态的高约束模式运行. 能量约束时间提高两倍以上,粒子的约束在较高密度下依然改善3倍以上.通过应用波扩散及 电流径向扩散方程计算低杂波电流传播的方法,对一组典型的数据进行数值模拟.计算表明 ,在HT-6M低杂波实验中,由于纵场较低,密度较高,低杂波的能量沉积在离磁轴较远的位 置,使等离子体电流密度分布成为反剪切位形,内部输运垒地形成,大大提高了等离子体的 约束状况.实验数据也给出了反剪切的证据.关键词：托卡马克低杂波约束改善 相似文献
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On the basis of a quantum‐statistical approach to the electrical conductivity of nonideal plasmas we derive analytical results in the classical low‐density regime, in the degenerate Born limit, and for the contribution of the Debye‐Onsager relaxation effect. These explicit results are used to construct an improved interpolation formula of the electrical conductivity valid in a wide range of temperature and density which allows to compare with available experimental data of nonideal plasmas. 相似文献