Laboratory modelling of equatorial ‘tongue’ accretion channels in young stellar objects caused by the Rayleigh-Taylor instability
Laboratory modelling of equatorial ‘tongue’ accretion channels in young stellar objects caused by the Rayleigh-Taylor instability
复制标题
由瑞利-泰勒不稳定性引起的年轻恒星中赤道“舌头”吸积通道的实验室模型
DOI：
10.1051/0004-6361/202140997
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发表时间：
2022
影响因子：
6.5
通讯作者：
Zemskov, R.
中科院分区：
文献类型：
--
作者：
Burdonov, K.;Yao, W.;Sladkov, A.;Bonito, R.;Chen, S.N.;Ciardi, A.;Korzhimanov, A.;Soloviev, A.;Starodubtsev, M.;Zemskov, R.
精确的三维磁流体动力学（MHD）模拟提出了由圆盘边缘瑞利-泰勒（RT）不稳定性发展引起的赤道吸积情景，但是这种现象还没有得到观测或实验的证实。产生的等离子体流穿过磁场，并研究这种结构是否可以缩放到年轻恒星天体（YSO）中赤道“舌头”吸积通道的情况;如果是这样的话，这将支持赤道吸积在年轻的吸积恒星的可能性。MethodsWe进行了一个规模的实验室实验在PEARL激光设施。该实验包括将光学激光脉冲聚焦到聚四氟乙烯目标的表面上。靶的照射导致热等离子体流垂直于外部施加的磁场膨胀到真空中。我们使用马赫-曾德尔干涉仪诊断等离子体流传播沿着两个轴，以获得三维分布的等离子体stream.ResultsThe实验室实验表明，横向扩展的激光产生的等离子体流的传播穿过磁场。我们证明：（i）这样的流经受RT不稳定性的发展，以及（ii）分解成舌状物的流能够有效地垂直于磁场传播。基于数值模拟，我们表明，在实验室中的不稳定性的发展的起源是类似的MHD模型中观察到的赤道舌吸积在YSOs.ConclusionsAs我们验证实验室等离子体尺度有利于吸积流入的YSOs，我们的实验室结果支持的论点赞成的可能性RT不稳定性引起的赤道舌吸积的情况下，在天体物理的情况下。
ContextThe equatorial accretion scenario, caused by the development of the Rayleigh-Taylor (RT) instability at the disk edge, was suggested by accurate three-dimensional magnetohydrodynamic (MHD) modelling, but no observational or experimental confirmation of such phenomena has been evidenced yet.AimsWe studied the propagation of a laterally extended laser-generated plasma stream across a magnetic field and investigated if this kind of structure can be scaled to the case of equatorial ‘tongue’ accretion channels in young stellar objects (YSOs); if so, this would support the possibility of equatorial accretion in young accreting stars.MethodsWe conducted a scaled laboratory experiment at the PEARL laser facility. The experiment consists in an optical laser pulse that is focused onto the surface of a Teflon target. The irradiation of the target leads to the expansion of a hot plasma stream into the vacuum, perpendicularly to an externally applied magnetic field. We used a Mach-Zehnder interferometer to diagnose the plasma stream propagation along two axes, to obtain the three-dimensional distribution of the plasma stream.ResultsThe laboratory experiment shows the propagation of a laterally extended laser-generated plasma stream across a magnetic field. We demonstrate that: (i) such a stream is subject to the development of the RT instability, and (ii) the stream, decomposed into tongues, is able to efficiently propagate perpendicular to the magnetic field. Based on numerical simulations, we show that the origin of the development of the instability in the laboratory is similar to that observed in MHD models of equatorial tongue accretion in YSOs.ConclusionsAs we verify that the laboratory plasma scales favourably to accretion inflows of YSOs, our laboratory results support the argument in favour of the possibility of the RT-instability-caused equatorial tongue accretion scenario in the astrophysical case.