Abstract

We report on results of investigation into the structure of a plasma jet generated by a coaxial plasma accelerator with conical insert in the discharge formation region. Using high-speed optoelectronic camera, we detected an inhomogeneous structure of glowing fractions of argon and deuterium jets. It was found that the jet radiation intensity oscillates with a characteristic frequency of 0.3–0.9 MHz. The argon plasma jet consisted of fragments diverging from the axis; plasma recombined 20 μs after the beginning of the discharge. The deuterium plasma jet resembled flakes. Its radiation intensity decreased significantly by 8 μs. The characteristic frequencies of radiation nonuniformities on the jet axis were about 0.09 cm^–1 for argon and 0.3 cm^–1 for deuterium. Analysis of the behavior of the discharge in the plasma accelerator revealed that a diffuse discharge was initiated at the base of the conical insert. After 0.5 μs, the discharge emerged at the outer boundary of the insert, was contracted, and occurred between central and external electrodes. The emergence of the discharge from the accelerator was observed 3 μs later and was accompanied with a glow of the end face of the central electrode. In the measurements of temperature of the lateral surface of external electrode using an infrared camera, it was found that heating is localized near the edge of conical insert and at the outlet of the accelerator. Results of investigations can be used for gas ionization, material irradiation, and simulation of interaction of plasma flows with the magnetic field in the outer space in laboratory conditions.

中文翻译：

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等离子加速器中放电形成的特殊性和进入真空的射流的结构

摘要

我们报告调查结果的同轴射流加速器与锥形插入在放电形成区域中产生的等离子体射流的结构。使用高速光电照相机，我们检测到了氩和氘射流的发光部分的不均匀结构。结果发现，射流辐射强度以0.3–0.9 MHz的特征频率振荡。氩等离子体射流由从轴向发散的碎片组成。放电开始后20 s内，等离子体重新结合。氘等离子体射流类似于薄片。其辐射强度显着降低了8μs。射流轴上辐射不均匀的特征频率大约为0.09 cm ^–1（氩气）和0.3 cm ^–1用于氘。对等离子加速器中放电行为的分析表明，在锥形插件的底部开始了扩散放电。0.5μs之后，放电出现在插件的外边界，收缩，并发生在中心电极和外部电极之间。3μs后观察到来自加速器的放电的出现，并且伴随着中心电极的端面的辉光。在使用红外热像仪测量外部电极的侧面温度时，发现加热集中在圆锥形插件的边缘附近和加速器的出口处。研究结果可用于气体电离，材料辐照，