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高度离化的中、高z元素激光等离子体辐射的细致结构能谱对惯性约束聚变等离子体诊断和原子结构理论计算等方面非常有用.在“神光Ⅱ”激光装置上,聚焦0.35μm激光束于真空室内的钼(Mo)元素固体靶上,产生Mo激光等离子体,用高分辨椭圆弯晶谱仪测量Mo激光等离子体辐射在0.32-0.58nm范围内的X射线细致结构能谱,并对实测能谱进行辨识和归类.辨识出了n=4—2,3—2系列离子共振跃迁和内壳层跃迁的能谱线,还有类氢、类氦离子共振线及伴线.另外,对谱线的半高全宽度(FWHM)值做了分析.在整个测量范围内,谱线精确波长值的绝对误差小于0.0005nm,与HFR方法得到的理论计算结果值比较,两者符合较好.此工作的结果对积累Mo元素离子谱线数据具有重要的意义. 相似文献
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对激光诱导等离子体参数进行诊断有多种方法,其中采用发射光谱法对其诊断是一种重要的方法。文中采用Nd∶YAG固态激光器,输出波长1 064 nm红外激光与铝合金样品相互作用,深入研究了铝合金等离子体产生早期(<1 μs)谱线轮廓、谱线强度、线背比、谱线半峰宽及位移等随时间演变规律。研究表明,激光与物质相互作用早期,电子数密度非常大,电子与离子及原子之间的相互作用非常强烈,谱线的Stark展宽效应非常明显,导致多重谱线重叠在一起,随时间演变,电子数密度及电子温度的降低,多重谱线的半峰宽越来越窄且谱线轮廓对称性越来越好。MgⅠ285.212 6 nm谱线强度早期逐渐增强,大约100 ns左右谱线强度达到最大值,然后谱线强度呈逐渐减小的趋势,这是由于等离子体产生早期,电子及离子占主导地位,故早期原子谱线强度较弱,随时间演变,电子与离子之间的复合,原子数密度逐渐增加,故原子谱线逐渐增强,达到最大值之后,由于等离子体激发温度的降低,故谱线强度逐渐减弱。以NIST波长位置为参考,等离子体产生的早期谱线发生了红移,连续背景强度随时间演变呈幂函数形式急剧递减,与之相反,谱线的连续背景强度与谱线强度相比,连续背景衰减的速度更为迅速,故导致谱线信背比随时间演变呈增大趋势,本研究对等离子体早期这些现象从理论角度进行了深入探讨。 相似文献
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等离子体光谱的多重结构 总被引:1,自引:1,他引:0
利用空间分辨的掠入式光栅谱仪和晶体谱仪等,获得了等离子体发射的软X射线多重连谱和伴线结构。软X射线多重谱主要由等离子体中多重电离态离子所致,而电子密度大小和杂质粒子对伴线丰度起主要作用。实验结果显示原子序数和入射激光强度与光谱结构的紧密联系以及等离子体发射源的非平衡性质。 相似文献
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利用一维拉格朗日流体动力学程序Med103详细研究了产生类镍Ag,Cd,In,Sn, Sb离子和类氖Fe,Co,Ni,Cu,Zn离子的等离子体状态.通过对电子温度、离子丰度、离子数密度等状态参量的分析比较,得到了这两类等离子体状态之间的对应关系.即类镍银的等离子体状态与类氖铁 的相近,类镍镉的与类氖钴的相近,依次类推.利用这一对应关系可以方便地由类氖机理x射线激光的等离子体状态来对相应元素的类镍x射线激光的等离子体状态进行判断.
关键词:
类氖
类镍
等离子体状态
x射线激光 相似文献
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本文详细叙述了利用He-like离子的特征谱线诊断等离子体的电子密度和电子温度的方法,给出了共振线与双电子伴线的强度比随电子温度的变化曲线和共振线与互组合线的强度比随电子密度的变化曲线。并且根据实验测得的上述两组谱线的强度比,定出激光产生等离子体的电子温度和电子密度。 相似文献
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在星光II激光装置上,采用PET平面晶体谱仪与宽20μm的狭缝构成一维空间分辨光谱测量系统,对金平面靶激光等离子体进行观测,获得了沿靶面法向一维空间分辨的金M带发射谱。在实验谱中观察到了Au元素类Ni离子的电四极跃迁线3p63d10(1S0) 3p53d104d(3/2,5/2)J=1。利用电四极跃迁线对电子密度的敏感特性,开展了金激光等离子体电子密度诊断的尝试,确定出利用该谱线进行电子密度诊断的有效范围大致在1019~4.5×1021cm-3之间。 相似文献
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A. N. Sil J. Anton S. Fritzsche P. K. Mukherjee B. Fricke 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,55(3):645-652
Spectral line positions for the highly stripped helium like carbon, aluminium and argon embedded in
intense plasma environments have been calculated theoretically to compare with the existing data
available from laser plasma experiments. The changes in the ionization potentials for such ions have
been determined and the excitation energies, oscillator strengths and transition probabilities for
the transitions 1s2
1S → 1snp 1P (n=2-5) have been evaluated for the diagnostic
determination of such plasmas. The ion sphere (IS) model was used for estimating the effect of strongly
coupled plasma on the ions within the non-relativistic as well as the relativistic framework. Time dependent
perturbation theory has been applied for obtaining the linear response properties of the ions in the
non-relativistic approximation. The effects of the plasma environment on such properties of the ions under
the Debye screening model with suitable cut off radii have also been considered for comparing the data with
those obtained from the IS model of the plasma. 相似文献
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Luther BM Wang Y Larotonda MA Alessi D Berrill M Marconi MC Rocca JJ Shlyaptsev VN 《Optics letters》2005,30(2):165-167
We report saturated operation of an 18.9-nm laser at 5-Hz repetition rate. An amplification with a gain-length product GL of 15.5 is obtained in the 4d 1S0-4p 1P1 laser line of Ni-like Mo in plasmas heated at grazing incidence with approximately 1-J pulses of 8.1-ps duration from a tabletop laser system. Lasing is obtained over a broad range of time delays and pumping conditions. We also measure a GL of 13.5 in the 22.6-nm transition of the same ion. The results are of interest for numerous applications requiring high-repetition-rate lasers at wavelengths below 20 nm. 相似文献
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《Physics letters. A》1996,210(3):195-197
X-ray spectra of highly ionized hafnium atoms have been obtained from laser produced plasmas in the 4.1–4.5 Å range. Using quasi-relativistic configuration interaction calculations of the wavelengths and transition probabilities, the observed spectral band structure can be interpreted as being due to 3d–6f transitions of the NiI—GeI like ionization states of hafnium. 相似文献
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利用Nd∶YAG激光作用于真空腔内的高纯固体钼(Mo)靶产生等离子体,并测量了不同脉冲激光功率密度下Mo等离子体在2~9 nm范围内的时间积分光谱。基于碰撞辐射平衡模型(CRM)和Cowan程序计算得到不可分辨跃迁峰(UTA)原子光谱数据,并假设谱线展宽为高斯线形,获得了在不同电子温度和电子密度下的理论模拟光谱,模拟光谱与实验光谱吻合的较好。实验与理论研究光谱表明:Mo ⅩⅥ-Mo ⅩⅫ离子的3d-4f不可分辨跃迁峰位于水窗波段,通过控制脉冲激光参数和采用合适的等离子体约束条件,获得水窗辐射波段Mo离子的高丰度布居,有望将激光Mo等离子用于单脉冲活体细胞显微成像水窗光源。 相似文献
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Modulation of ionization on laser frequency in ultra-short pulse intense laser--gas-target 下载免费PDF全文
Based on the dispersion relation of intense laser pulse propagating in gradually
ionized plasma, this paper discusses the frequency modulation induced by ionization
of an ultra-short intense laser pulse interacting with a gas target. The
relationship between the frequency modulation and the ionization rate, the plasmas
frequency variation, and the polarization of atoms (ions) is analysed. The numerical
results indicate that, at high frequency, the polarization of atoms (ions) plays a
more important role than plasma frequency variation in modulating the laser
frequency, and the laser frequency variation is different at different positions of
the laser pulse. 相似文献
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Temporally resolved emission spectra (360-630 nm) of carbon ablation plasmas produced during laser hole boring by a 25-ns duration 1-J ruby laser pulse are presented. The emitted line radiation originates from, C+++ to C+ depending upon the time relative to the laser pulse. Plasma temperatures of 12-14 eV during the laser pulse to about 4 eV, 140 ns after the laser pulse are obtained by comparing the spectroscopic results to a collisional-radiative equilibrium (CRE) model which bridges the gap between the local thermodynamic equilibrium (LTE) model and the coronal model. 相似文献
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R.W. Lee B.L. Whitten R.E. Stout 《Journal of Quantitative Spectroscopy & Radiative Transfer》1984,32(1):91-101
X-ray spectroscopy is a powerful tool for understanding the kinetics of highly ionized plasmas. Its usefulness depends on the accuracy of the model used in analyzing spectra. We have developed a computer code for modeling and analyzing plasmas which is highly accurate as well as fast and easy to use. It produces synthetic spectra for hydrogen-like and helium-like ions at arbitrary density and temperature. Populations are calculated from rate equations including all relevant collisional and radiative process. The level populations of the hydrogen, helium and lithium-like ionization stages are calculated explicitly; those of all other ionization stages are lumped into one level. The microfield distribution and the shape of the line profiles are determined using detailed calculations. The code includes graphics to plot line ratios and synthetic spectra, and to do on-line analysis of experiments. The usefulness of this technique is demonstrated by analyzing the spectra from three different experiments: a laser irradiated aluminum disk; a neon gas puff pinch; and a laser imploded gas microballon. 相似文献
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Ultracold neutral plasmas are strongly coupled Coulomb systems that are generated by photoionizing lasercooled atoms close to the ionization threshold. The strong coupling parameter Γ is limited at times later than ~100 ns by disorder‐induced heating. A recent simulation predicted that higher values of Γ can be realized in ultracold neutral plasmas if the plasma ions are excited to higher ionization states. In this paper we present recent results from an experiment that increases the strong coupling of an ultracold neutral plasma by promoting the plasma ions to the second ionization state. Using laser‐induced fluorescence we map out the ion velocity distribution of the Ca+ ions in a partially doubly ionized plasma and show that the heating due to the second ionization depends on the timing of the second ionization laser pulses. We compare our results to MD simulations, which estimate that Γ increases from approximately 2.5 to 3.6. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献