【摘要】 强流脉冲离子束辐照靶材产生烧蚀等离子体向背景气体中传播与向真空中传播不同,包括喷发等离子体与背景气体的相互作用.本文建立了该过程的二维气体动力学模型,计算了等离子体向压强范围从10-6大气压到大气压背景气体中传播时的情况.结果表明,背景气体压强不同时,等离子体传播的现象也不相同.向真空中可以自由膨胀,向大气压中膨胀受限;当背景气压在千分之一大气压左右时,等离子体在背景气体中形成“雪犁”状,羽状等离子体出现快速和慢速传播分离现象.更多还原

【Abstract】 The mechanisms are different for intense pulsed ion beam ablation plasma expanding into ambient gas of different pressure or into vacuum. The former is complicated by the interaction between plasma and the ambient gas. The 2D gas dynamical model has been built to describe the process, and the plasma expansion into ambient gas of pressures from 10~ -6 atmosphere to 1 atmosphere have been calculated. The results show that the phenomena of plasma expanding into ambient gases vary as the pressure changes. It can expand into vacuum freely, but into atmosphere its movement is confined. And the ejection into ambient gas of one thousandth atmosphere or so is special, the ‘snowplow’ phenomenon is observed and the plume plasma splits into fast_ and slow_moving parts.更多还原