Experimental study of magnetic bubble expansion as a model for extragalactic radio lobes

这个项目将进行实验室实验和协调的数值模拟，以帮助解决悬而未决的等离子体物理问题，这些问题与银河系外喷流携带的磁能和螺旋度如何与星系间介质达到准平衡有关，形成被认为是巨大松弛等离子体的巨大“射电叶”。这些实验将研究磁化等离子体气泡在膨胀到较低气压背景等离子体并与之达到平衡时的弛豫。主要的科学目标是描述气泡弛豫的基本非线性等离子体物理，包括磁通量转换、离子和电子加热以及角动量演化/输运。这些非线性等离子体物理问题目前不能仅靠数值计算或天文观测来解决。实验结果将提供对气泡膨胀/松弛过程的深入了解，并为验证该领域正在进行的数值计算提供必要的数据。将调整实验参数，以便与磁通量、电流、螺旋度注入速率(和持续时间)和总注入螺旋度有关的重要无量纲参数与天体物理环境相关。

0613577LynnThis project will conduct laboratory experiments and coordinated numerical modeling to help address outstanding plasma physics issues related to how magnetic energy and helicity carried by extra-galactic jets reach quasi-equilibrium with the intergalactic medium, forming gigantic 'radio lobes' which are thought to be gigantic relaxed plasmas. The experiments will study the relaxation of a magnetized plasma bubble as it expands into and reaches equilibrium with a lower pressure background plasma. The primary scientific objectives are to characterize the underlying nonlinear plasma physics of the bubble relaxation, including magnetic flux conversion, ion and electron heating, and angular momentum evolution/transport. These nonlinear plasma physics issues cannot at present be resolved from numerical computation or astronomical observations alone. The experimental results will provide insights into the bubble expansion/relaxation process and the needed data for validating numerical computations being carried out in this field. Experimental parameters will be adjusted so that important dimensionless parameters relating to magnetic flux, electric current, helicity injection rate (and duration), and total injected helicity are relevant for the astrophysical context.