【作者】 谢锦林；

【导师】 俞昌旋； 刘万东；

【作者基本信息】 中国科学技术大学 ， 等离子体物理， 2008， 博士

【摘要】 本论文的主要工作包括线性磁化稳态等离子体装置及半导体激光诱导荧光诊断系统的建设,并利用这两个平台开展的相应实验研究。在论文工作期间,成功建立了国内首个中等尺寸的线性磁化稳态装置,并通过热丝直流及射频放电两种等离子体产生方式,使得线性实验区等离子体参数具有较大调控范围,如等离子体密度、电子温度及离子温度等,为装置上物理实验研究的开展奠定了较好的基础。在线性磁化装置上较为系统的开展了漂移波的实验研究。通过研究涨落模式的磁场阈值及其传播特征,验证了磁化等离子体柱中的低频涨落为密度梯度驱动的漂移波不稳定性;利用双谱、线性增长率以及幅度相关等谱分析手段较全面的研究了漂移波模式之间的非线性相互作用,发现涨落模式之间存在较强的非局域的三波相互作用,且能量从高频转移低频。在磁场增大的过程中,悬浮电位及离子饱和流的自功率谱中低频处的能量都相应增大。实验中发现在一定参数条件下存在极向波数为零、频率范围在0～2KHz的无色散模式,与低频带状流较为类似。由漂移波涨落导致的径向粒子输运通量计算等效扩散系数,发现等效的扩散系数大约是经典输运系数的两倍,远小于玻姆扩散系数。成功的利用半导体激光器组建了激光诱导荧光诊断系统,并详细的讨论了LIF诊断中各种因素带来的展宽机制。在表面多极约束的非磁化等离子体中,实验研究了荧光强度与泵浦光强、等离子体参数、外部控制参数的依赖关系,有利于今后LIF实验中进行荧光强度优化。另外还通过荧光恢复的时序信息估算了离子的扩散系数。更多还原

【Abstract】 A linear magnetized steady plasma device was successfully set up in USTC. Hot filament DC discharge and RF helicon discharge applied in the device provide a wide range of plasma parameters, such as density, electron temperature.The low frequency fluctuation observed in the magnetized plasma column was identified as density gradient driven drift wave. From the analysis of bi-spectrum, nonlinear energy transfer function and amplitude correlation, strong wave-wave interaction was observed and the energy was transferred from high frequency part to low frequency. Some low frequency zonal flow like structures were also found. The drift instability induced radial transport exceeds the classical transport, but is below the Bohm value.Laser Induced Fluorescence diagnostic was build up. The cheap and ease-use diode laser was chosen as the pump laser source, instead of the expensive dye laser. It was found that the metastable state argon ions were mostly produced via the one-step ionization. The intensity of induced fluorescence was optimized by carefully choosing the proper neutral pressure, discharge voltage and pumping laser power. From the recovery of the background fluorescence, we deduced the ion diffusion coefficient, which agreed with the result from the damping of Ion Acoustic Wave.更多还原