Abstract

The use of Z-pinch facilities makes it possible to carry out well-controlled and diagnosable laboratory experiments to study laboratory jets with scaling parameters close to those of the jets from young stars. This makes it possible to observe processes that are inaccessible to astronomical observations. Such experiments are carried out at the PF-3 facility (“plasma focus,” Kurchatov Institute), in which the emitted plasma emission propagates along the drift chamber through the environment at a distance of one meter. The paper presents the results of experiments with helium, in which a successive release of two ejections was observed. An analysis of these results suggests that after the passage of the first supersonic ejection, a region with a low concentration is formed behind it, the so-called vacuum trace, due to which the subsequent ejection practically does not experience environmental resistance and propagates being collimated. The numerical modeling of the propagation of two ejections presented in the paper confirms this point of view. Using scaling laws and appropriate numerical simulations of astrophysical ejections, it is shown that this effect can also be significant for the jets of young stars.

中文翻译：

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天体物理和实验室射流的准直传播原因

摘要

Z-pinch 设施的使用使得进行控制良好和可诊断的实验室实验成为可能，以研究实验室喷流的比例参数接近年轻恒星喷流的比例参数。这使得观察天文观测无法实现的过程成为可能。此类实验在 PF-3 设施（“等离子体焦点”，库尔恰托夫研究所）进行，其中发射的等离子体发射沿漂移室传播，穿过环境，距离一米。该论文介绍了氦实验的结果，其中观察到连续释放两次喷射。对这些结果的分析表明，在第一次超音速喷射通过后，在其后面形成了一个低浓度区域，即所谓的真空轨迹，因此，随后的喷射实际上不会受到环境阻力，并且会被准直传播。论文中提出的两次喷射传播的数值模拟证实了这一观点。使用缩放定律和适当的天体物理抛射数值模拟，表明这种效应对于年轻恒星的喷流也很重要。