Precursor electron density measurement ahead of strong shock waves
Precursor electron density measurement ahead of strong shock waves
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强冲击波前的前驱体电子密度测量
DOI：
10.1063/1.1407638
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
T. Abe
中科院分区：
文献类型：
--
作者：
K. Fujita;A. Matsuda;S. Sato;T. Abe
为了了解在激波管实验中观察到的强激波背后的快速电离过程，我们用三探针法测量了前驱区的瞬变等离子体性质，具有较高的信噪比和时间分辨率。用氮气作为试验气体，观察到前驱体中的电子密度随着激波的接近而迅速增加，而激波前的电子温度几乎是均匀的。结果表明，电子密度强烈依赖于激波速度，而电子温度对激波速度不太敏感。在激波速度为12.4 km/S时，电子密度达到1019 m−3，在激波前20 mm处的电子温度为7000K。如此大量的电子被认为允许甚至比激波后的传统电离模型所预期的更猛烈的电子碰撞电离。
In order to understand the fast ionization process behind the strong shock wave observed in the previous shock-tube experiment, we measure the transient plasma properties in the precursor region by means of the triple-probe method with the high signal/noise ratio and time resolution. Using nitrogen as the test gas, the electron density in the precursor is observed to increase very quickly as the shock wave approaches, while the electron temperature is almost uniform ahead of the shock wave. The electron density is found to depend strongly upon the shock velocity, while the electron temperature is less sensitive to the shock speed. At the shock velocity of 12.4 km/s, the electron density amounts to 1019 m−3, and the electron temperature is 7000 K at 20 mm ahead of the shock wave. Such a large number of electrons are considered to allow the much more vigorous electron-impact ionization even immediately behind the shock wave than expected by the conventional ionization models behind the shock wave.