激光场影响下离子在等离子体中能量损失的研究

发布时间：2018-03-28 03:30

本文选题：阻止本领　切入点：能量损失　出处：《大连海事大学》2017年硕士论文

【摘要】：带电粒子与等离子体相互作用过程中的能量损失与不同科学领域的许多应用有关,例如重离子惯性约束聚变,磁约束聚变,重离子电子冷却等。20世纪80年代,啁啾脉冲放大技术为激光技术的发展创造了良好的条件,引发了人们研究在激光场影响下带电粒子与等离子体相互作用的能量损失问题。特别是,随着加速器技术的发展,产生高速重离子已经成为可能,同时受重离子惯性约束聚变技术的发展需要,促进了人们开展激光场影响下离子能量损失问题的研究。本文在伏拉索夫-泊松方程理论模型的基础上,采用分子动力学模拟方法,利用线性介电响应理论和Brandt-Kitagawa有效电荷理论,推导了原子离子在等离子体中的相互作用势和阻止本领表达式,进一步讨论了激光参数对原子离子与等离子体相互作用过程中能量损失的影响。首先我们在给定激光角度α= π/3、等离子体密度n_0=10~(16)cm~(-3)、电子温度T_e=3eV的情况下,研究了硼原子离子在激光场影响下的能量损失情况。在研究过程中我们发现激光场强对硼原子离子的能量损失具有一定的影响,发现其阻止本领随着速度的增加呈现先增加后减小的趋势,且随着激光场强的增加硼原子离子的阻止本领不断减小。另外,研究发现硼原子离子的阻止本领还受到激光频率和激光角度的影响。氮原子离子模拟结果随激光参数的变化规律方面与硼原子离子的模拟结果具有类似的结论,但由于它们核电荷数的不同,导致同一激光场强度下它们的阻止本领不同。为此又对氧原子离子进行了模拟探究,结果发现:在同一激光场强度(a_E=3λ_D)下,氧原子离子的阻止本领大于氮原子离子的阻止本领,氮原子离子的阻止本领又大于硼原子离子的阻止本领,即对于不同的原子类型,阻止本领随核电荷数的增加而增大。通过以上对硼原子离子、氮原子离子、氧原子离子的模拟,结果表明:激光场强度是影响原子离子与等离子体之间相互作用的一个重要参数。随着激光强度的增加,阻止本领不断减小;原子离子的阻止本领随着速度的增加呈现了先增大而后减小的趋势;另外,激光频率、激光角度也能够对阻止本领起到调制作用;随着原子离子核电荷数的增加,原子离子的阻止本领会不断增大。
[Abstract]:The energy loss in the interaction between charged particles and plasma is related to many applications in different scientific fields, such as heavy ion inertial confinement fusion, magnetic confinement fusion, heavy ion electron cooling and so on. Chirped pulse amplification has created favorable conditions for the development of laser technology, which has triggered the study of the energy loss of the interaction between charged particles and plasma under the influence of laser field, especially with the development of accelerator technology. It has become possible to produce high speed heavy ions, and the development of heavy ion inertial confinement fusion technology is needed. In this paper, based on the theoretical model of Volasov Poisson equation, molecular dynamics simulation method, linear dielectric response theory and Brandt-Kitagawa effective charge theory are used. The expressions of the interaction potential and stopping power of atomic ions in plasma are derived. The effect of laser parameters on the energy loss during the interaction of atomic ions with plasma is further discussed. Firstly, under the given laser angle 伪 = 蟺 / 3, plasma density n010 / 10 and electron temperature T_e=3eV, The energy loss of boron ion under the influence of laser field is studied. In the course of the study, we find that the laser field intensity has a certain effect on the energy loss of boron ion. It is found that the blocking power increases first and then decreases with the increase of the velocity, and decreases with the increase of the laser field strength. It is found that the blocking power of boron ion is also affected by laser frequency and laser angle. However, because of the difference of their nuclear charge number, they have different blocking power under the same laser field intensity. Therefore, the oxygen atom ion is simulated and studied. The results show that under the same laser field intensity, The blocking power of oxygen atom ion is greater than that of nitrogen atom ion, and that of nitrogen atom ion is greater than that of boron atom ion, that is, for different atomic types, The blocking power increases with the increase of the number of nuclear charges. The results show that the laser field intensity is an important parameter affecting the interaction between atomic ions and plasma, and the stopping power decreases with the increase of laser intensity. The blocking power of atomic ions increases first and then decreases with the increase of the velocity; in addition, the laser frequency and laser angle can also modulate the blocking power; as the number of atomic ion nuclear charges increases, The blocking power of atomic ions increases.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN249;O53

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