医用微波常压室温等离子体激发机理研究

The room temperature atmospheric-pressure plasma ignited by microwave with mix gases shows a huge potential in the treatment of cancer, due to it can selectively kill the cancer cells and meet the requirement of being employed in open space in clinical application. Different cancer cells are sensitive to different active particles. However, the research on excitation mechanism of room temperature atmospheric-pressure plasma ignited by microwave is found seriously insufficient, which leads to few existed relevant devices, low efficiency and failure in quantitative characterization and precisely controlling of the active particles and their concentrations in plasma. Its clinical applications are therefore greatly limited. In view of this, this project, initially based on the ambipolar diffusion theory and optical emission spectroscopy method, applying theoretically simulation and experimental analysis to discover the excitation mechanism of room temperature atmospheric-pressure plasma ignited by microwave. It includes:1) with the previous self-designed prototype, measuring and concluding the effects of microwave energy and gas parameters on plasma by the optic emission spectroscopy method;2)based on the experimental results and the ambipolar diffusion theory, exploring the accurate and high-efficient mathematical model and calculation method for microwave ignited room-temperature atmospheric plasma;3) simulating and analyzing the influence of apparatus structure, microwave parameters and gas parameters on plasma; combing the simulated analysis and experimental consequences to investigate the excitation mechanism of room temperature atmospheric-pressure plasma ignited by microwave and design a high-efficient microwave ignited room-temperature atmospheric pressure plasma device for cancer treatment.

采用混合气体的微波常压室温等离子体因其对癌细胞的选择性灭活作用和满足临床对开放空间的需求，在癌症辅助治疗领域表现出了巨大潜力。不同癌细胞需要不同的活性粒子来处理。然而目前微波常压室温等离子体的激发机理研究还严重不足，致使相关装置寥寥无几，效率不高，尚无法实现对等离子体中活性粒子种类及浓度的定量表征和精确调控，极大限制了其临床应用。因此，本项目将创新性地基于双极化扩散理论和发射光谱法，采用理论模拟与实验分析相结合的方式来探索微波常压室温等离子体的激发机理。主要包括：1）结合前期设计的相关装置，利用发射光谱法测量并总结微波与气体参数对等离子体性质的影响；2）基于实验结果和双极化扩散理论，探索高效准确的微波常压室温等离子体模型与计算方法；3）仿真分析装置结构、微波、工作气体对等离子体参数的影响，结合实验结论来探讨微波大气压室温等离子体的激发机理，并设计用于癌细胞处理的高效微波常压室温等离子体源。

微波常压室温等离子体在生物医疗领域如癌症辅助治疗方面表现出了巨大应用潜力。本项目针对目前微波常压室温等离子体的激发机理研究还严重不足，相关装置少且效率不高，尚无法实现对等离子体中活性粒子种类及浓度的定量表征和精确调控等问题，利用前期设计的同轴等离子体装置和发射光谱法，探索了微波参数（功率、频率）和气体参数（气体流速、气体种类，混合比例）对大气压等离子体激发及其性质的影响，并总结了影响规律；精简等离子中的化学反应，采用双极化扩散近似代替传统的漂移扩散假设来合理简化方程系统，利用scaling方法将原问题的数量级相对统一化，从而弱化模型对网格密集度的要求和避免不收敛情况，使用隐式和准隐式算法来求解电子输运方程和离子输运方程，突破方程求解时间步长的限制，采用Benoy微分方程法等加快模型计算速度，建立了一个既节省计算资源，又保证计算准确度的模型与快速计算方法；仿真计算了微波参数和气体参数对等离子体性质的影响及电磁波在等离子体中的传播情况，结合前期实验结果，研究了微波大气压室温等离子体的激发机理，并设计了一款便携、高效的微波常压室温等离子体源。该源仅需5W的输入功率，即可自激发氩气产生等离子体。本项目的研究将有助于微波常压室温等离子体激发机理的研究，为相关微波常压室温等离子体源的高效设计提供强有力的理论支持。该项目对于我国的医疗事业和人民的生命健康具有重要意义。