【摘要】 利用一维自洽流体模型系统研究了大气压条件下纵向氦气流对直流辉光放电特性的影响.研究结果表明,在不同的氦气流速条件下,对应不同放电空间中带电粒子的动力学行为特征表现出显著的差异,进而引起放电结构的变化.正向氦气流导致放电空间中正柱区和负辉区的带电粒子密度减少,甚至能够使得负辉区逐渐消失.负向氦气流能够使得放电空间负辉区的带电粒子密度增大.通过比较氦气流速与离子迁移速率的差异,分析结果发现,因氦气流导致对流效应,其通过不同方式影响放电空间带电粒子的输运机制,最终引起了放电空间结构行为特性的变化.等离子体密度的增加说明在实际应用中通过控制气流大小和方向可以提高等离子体源的化学活性和工作效率,这对于等离子体在工业领域中的应用具有一定的参考和指导意义.更多还原

【Abstract】 A one-dimensional self-consistent fluid model was developed to study the direct-current(DC) glow discharge in longitudinal flowing helium(He) at atmospheric pressure. Distinct dynamical features of charged particles are observed at different He flow velocities, which is accompanied by a dramatic change of spatial discharge structure. The positive He flow leads to the reduction of charged particle densities in the positive column and negative glow regions, and even makes the negative glow region disappear. The negative He flow allows for the enhancement of charged particle densities in the negative glow regions. These observations above mainly lie in the fact that the convection effects due to the He gas flow influence the transport properties of charged particles through different ways by comparing the He flow velocity with the ion drift one. These findings are of guiding significance for the improvement of the chemical activity and work efficiency of plasma source by controlling the gas flow in practical industrial fields.更多还原