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1.
本文假定等离子体局部压强梯度由理想磁流体高n气球模所限定,讨论了非圆截面环流器的最佳压强剖面。分析了椭圆及三角变形的效应,发现三角变形对提高稳定性很有利;q剖面对平均比压值及中心比压值都有强烈影响,而沿半径下降的q剖面对提高比压值很有利。 相似文献
2.
对强流脉冲离子束(IPIB)辐照Ti靶的烧蚀效应进行了二维数值研究.得到了表面烧蚀物质随脉冲时间的变化关系.得出TEMP Ⅱ 型加速器产生的脉冲束流辐照靶材时引起的汽、液化均是从表面开始、并且汽化过程中表面物质被层层烧蚀的结论.同时,得到中心区的平均烧蚀速度为10m/s 数量级,它远小于产生的烧蚀等离子体的喷发速度.得到脉冲期间靶材内部不同位置烧蚀斑痕形状的时间演化过程,以及束流中含有的离子种类分额不同时IPIB辐照过程产生的不同效果.
关键词:
强流脉冲离子束
靶
烧蚀过程
二维数值模拟 相似文献
3.
We theoretically investigate the dust charging in the sheath of an electronegative plasma, by using a single dust grain model based on a previous sheath structure [Chin. Phys. Lett 20 (2003) 1537] in which cold positive ions and hot negative ions have been assumed. It is found that dust grains are first charged negatively at the sheath 相似文献
4.
Two-dimensional numerical research on effects of titanium target bombarded by TEMPⅡ accelerator 下载免费PDF全文
Two-dimensional numerical research has been carried out on the ablation effects of
titanium target irradiated by intense pulsed ion beam (IPIB) generated by TEMP II
accelerator. Temporal and spatial evolution of the ablation process of the target
during a pulse time has been simulated. We have come to the conclusion that the
melting and evaporating process begin from the surface and the target is ablated
layer by layer when the target is irradiated by the IPIB. Meanwhile, we also
obtained the result that the average ablation velocity in target central region is
about 10\,m/s, which is far less than the ejection velocity of the plume plasma
formed by irradiation. Different effects have been compared to the different ratio
of the ions and different energy density of IPIB while the target is irradiated by
pulsed beams. 相似文献
5.
利用拟合实测的TEMP Ⅱ型加速器磁绝缘二极管(MID)电压波形及其焦点附近束流密度曲线,建立了Gaussian分布模型,据此计算了与靶作用的离子的能量及数量,采用Monte Carlo(MC)方法计算了沉积在靶内的能量.并以此作为热源,与流体动力学(HD)模型相结合,对不同的靶状态采用相应的状态方程,模拟计算了靶内压力演化情况; 同时对烧蚀产生的等离子体采用理想气体状态方程, 结合HD方程组, 模拟计算了喷发过程中压力的空间演化过程.
关键词:
强流脉冲离子束
Gaussian模型
HD方程
数值研究 相似文献
6.
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. 相似文献
7.
We theoretically investigate the dust charging in electronegative silane (SiH4) plasmas, taking into account the effects of UV photodetachment. It is found that UV photodetachment could significantly lower the dust negative charge and even makes dust grains be positively charged under some special conditions. In addition, the other parameters, involving the negative ion and dust number densities, electron temperature and dust radius, have great effects upon the dust charging. 相似文献
8.
9.
A two-flux radiation model of the helical instability of arcs in axial magnetic field is presented. The temperature (and electrical conductivity) is approximated in a more realistic way (parabolic instead of flat profile) and a simplified term of radiation losses is included in the energy equation. The magnetohydrodynamic equations in an electrostatic approximation serve as the starting point of the theorv. Using a linear time-dependent perturbation theory, the corresponding equations and an explicit analytic expression that corresponds to the term of radiation losses are derived in the presence of the radiation transfer energy, from which the marginal Maecker number and the growth rate of the helical instability can be given. It is found that, in comparison with the results without radiation, the arc stable area is reduced. 相似文献
10.
Numerical studies of atmospheric pressure glow discharge controlled by a dielectric barrier between two coaxial electrodes 总被引:1,自引:0,他引:1 下载免费PDF全文
The glow discharge in pure helium at atmospheric pressure, controlled
by a dielectric barrier between coaxial electrodes, is investigated
based on a one-dimensional self-consistent fluid model. By solving
the continuity equations for electrons, ions, and excited atoms, with
the current conservation equation and the electric field profile, the
time evolution of the discharge current, gas voltage and the surface
density of charged particles on the dielectric barrier are
calculated. The simulation results show that the peak values of the
discharge current, gas voltage and electric field in the first half
period are asymmetric to the second half. When the current reaches
its positive or negative maximum, the electric field profile, and the
electron and ion densities represent similar properties to the
typical glow discharge at low pressures. Obviously there exist a
cathode fall, a negative glow region, and a positive column. Effects
of the barrier position in between the two coaxial electrodes and the
discharge gap width on discharge current characteristics are also
analysed. The result indicates that, in the case when the dielectric
covering the outer electrode only, the gas is punctured earlier
during the former half period and later during the latter half period
than other cases, also the current peak value is higher, and the
difference of pulse width between the two half periods is more
obvious. On reducing the gap width, the multiple current pulse
discharge happens. 相似文献