Intensities of atomic lines and molecular bands observed in impact-induced luminescence
Intensities of atomic lines and molecular bands observed in impact-induced luminescence
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DOI：
10.1029/2003je002156
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发表时间：
2003-12
影响因子：
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通讯作者：
S. Sugita;P. Schultz;S. Hasegawa
中科院分区：
文献类型：
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作者：
S. Sugita;P. Schultz;S. Hasegawa
在美国宇航局艾姆斯垂直靶场进行了一系列超高速撞击实验，使用球形铜弹和多晶白云岩目标。利用高速光谱仪系统测量了每次撞击后2微秒内原子谱线和分子谱带的强度，并以固定撞击角度（距水平45°）下的撞击速度（2 - 5.5 km/s）为函数进行了评估。虽然测量到的发射强度很好地遵循幂律关系，但各个发射线和波段的幂律指数差异很大，范围在2.1到9.1之间。相比之下，波长积分可见光强度（435-650 nm）的指数约为5。如此大的指数变化表明幂律关系的复杂性。为了理解控制幂律关系的物理过程，建立了考虑分子和原子的化学平衡、原子的电子激发和电离的理论模型。该模型很好地解释了观测到的幂律指数的变化。这种模式将提供一个物理框架，用于预测对行星表面的人为和自然撞击的排放强度，并根据排放强度估计撞击者的大小。
[1] A series of hypervelocity impact experiments were conducted at NASA Ames Vertical Range, using spherical copper projectiles and polycrystalline dolomite targets. The intensities of atomic lines and molecular bands in the first 2 microseconds after each impact were measured using a high-speed spectrometer system and assessed as functions of impact velocity (2–5.5 km/s) at a fixed impact angle (45° from the horizontal). Although the measured emission intensities follow power law relations well, the power law exponents of individual emission lines and bands are very different, ranging from 2.1 to 9.1. In contrast, the exponent for wavelength-integrated visible light intensity (435–650 nm) is about 5. Such a large variation in exponents suggests a complex nature for the power law relations. In order to understand the physical processes controlling the power law relations, a theoretical model is developed considering chemical equilibrium of both molecular and atomic species, the electronic excitation of atoms, and ionization. This model accounts for the observed variety of the power law exponents well. Such a model will provide a physical framework for predicting the emission intensities from both artificial and natural impacts on planetary surfaces and for estimating size of an impactor from the emission intensity.