Knot structures exist ubiquitously in young stellar object (YSO) jets, which are a key tracer in astronomical observation to estimate the jet properties and eventually the YSO’s parameters (age, size, mass and so on). Using 2D and 3D radiation magnetohydrodynamic simulations of the laser-produced plasma jets in external poloidal magnetic fields, we present a systematic analysis on the formation mechanism and characteristics of knot structures in collimated jets. The simulations demonstrate that the multi-knot pattern in jets can be formed by the oblique internal shocks in only single ejection. It is found that the distance L between different knots in jet is determined by the ratio of its thermal pressure to magnetic pressure β as ##IMG## [http://ej.iop.org/images/0741-3335/62/9/095020/ppcfaba4beieqn1.gif] {$L\propto D\beta^{1/2}$} , where D is the jet transverse diameter. There is a factor about 0.4-0.6 between the knot and jet velociti...

中文翻译：

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实验室激光驱动等离子体对原星尺度射流结结构的数值研究

结状结构普遍存在于年轻的恒星天体（YSO）喷流中，这是天文观测中估算喷流特性并最终估算YSO参数（年龄，大小，质量等）的关键示踪剂。使用外部极向磁场中激光产生的等离子体射流的2D和3D辐射磁流体动力学模拟，我们对准直射流中结结构的形成机理和特征进行了系统分析。仿真表明，在单次喷射中，倾斜的内部冲击可以形成喷射中的多结图案。发现射流中不同结之间的距离L由其热压与磁压β之比确定，如## IMG ## [http://ej.iop.org/images/0741-3335/62/ 9/095020 / ppcfaba4beieqn1.gif] {$ L \ propto D \ beta ^ {1/2} $}，其中D是射流横向直径。结速度和射流速度之间存在约0.4-0.6的因数...