Physics and Simulation of Helicon Plasma Sources

本研究的目标包括对螺旋等离子体源（n_e=10^11 - 10^13/cm^3）进行新的实验测量和计算模拟，这对未来的各种应用都很重要。这些包括亚微米等离子体蚀刻晶圆，材料的处理，氩激光器的有效电离源，空间等离子体实验模拟的大体积源，聚变等离子体约束实验的源，核废料处理器，以及作为空间飞行器的推力器。这些来源迄今尚未解决的关键问题是：1)快速电离电子（e16 eV）的产生机制及其能量时空分布函数的测量，这是螺旋源高效电离的关键；2)波在非均匀磁场结构中的快速空间阻尼机制和改进源操作的新型天线的实现；3)波天线耦合、线性加热和非线性波捕获过程的二维模拟。该方法可与实验观测结果进行比较，并可用于预测未来螺旋源的性质，这是该领域的新技术。我们开发了一种新的实验设备，该设备将利用快速响应光学探针、指示快速电子的高能氩态光谱、波场、频谱分析、朗缪尔探针和抗磁环以及网络分析仪技术来测量匹配的天线阻抗。我们将开发一个二维等离子体轮廓，有限差分，全电磁代码（MAXEB），并将其与实验观测进行比较。提高对等离子体产生的物理和模拟技术的理解将为大大改进天线和磁场源的设计以及各种应用的更大尺寸等离子体源提供基础。我们的新实验程序与模拟程序的紧密耦合为提高我们在这一新兴技术领域的未来应用的知识提供了一个绝佳的机会

Scharer9905948The objectives of this research include new experimentalmeasurements and computational simulations of heliconplasma sources (n_e=10^11 - 10^13/cm^3) which areimportant for a variety of future applications. Theseinclude submicron plasma etching of wafers, processingof materials, an efficient ionization source for argonlasers, a large volume source for simulation of space-plasmaexperiments, a source for fusion plasma confinementexperiments, a processor of nuclear waste, and as athrustor for space vehicles. Key issues which have notbeen resolved to date for these sources are: 1) Mechanismsfor producing fast ionizing electrons (in argon E 16 eV)and measurements of their energy distribution function inspace and time, which are key to efficient ionization in heliconsources, 2) Mechanisms for rapid spatial damping of the wavein inhomogeneous magnetic field configurations and realizationof new antennas which improve source operation, 3) 2-Dsimulations of wave antenna coupling, linear heating, andnonlinear wave trapping processes, which can be comparedwith experimental observations and utilized to predict futurehelicon source properties which is new to the field. We havedeveloped a new experimental facility which will utilize asdiagnostics a fast response optical probe, spectroscopyof energetic argon states indicative of fast electrons, wavefield, frequency spectral analysis, Langmuir probe anddiamagnetic loops and network analyzer techniques tomeasure the matched antenna impedance. We will develop a 2-D plasma profile, finite-difference, full electromagnetic code (MAXEB) which will be compared with experimental observations. The improved understanding of the physics of plasma production and simulation techniques for these sources will provide a basis for greatly improved antenna and magnetic field source design and larger size plasma sources for a variety of applications. The close coupling of our new experimental program with simulation programs provides an exceptional opportunity for improving our knowledge for future applications in this emerging technology area.***