CAREER: Intermittency and Two-Fluid Transitions in Pulsed-Power-Driven Magnetized Turbulence

该奖项支持在实验室中研究湍流等离子体物理的研究计划。 湍流存在于我们每天所经历的流体中。湍流的不可预测性限制了我们对从天气到航空旅行等一切事物的预测能力。湍流也存在于等离子体中--构成可见宇宙大部分的炽热电离气体。等离子体湍流在从黑洞吸积盘到星际介质的广泛的天体物理现象中起着重要作用，在星际介质中，湍流的加热使有机分子的形成成为生命的基石。等离子体湍流也限制了未来潜在的聚变能反应堆的性能。该研究计划将开发一个在实验室中产生湍流等离子体的新平台和测量等离子体湍流的新方法。该奖项还支持开发开放式等离子体实验室课程的实质性努力，其中包括设计，构建和测试其他教师可以轻松复制的实验室实验。如果成功的话，这一努力将通过将等离子体物理学教学推广到更广泛的教育机构来加强美国STEM的劳动力。就像流体动力学湍流是由流体运动的漩涡建立的一样，磁化等离子体湍流是由磁岛和电流片建立的，它们用于在不同的空间尺度之间传递磁能。该项目将使用内爆碳丝阵列Z箍缩，由马萨诸塞州理工学院的新PUFFIN发生器驱动，作为磁岛合并平台来产生磁化等离子体湍流。这种磁化等离子体湍流将处于以前未探索的状态：持续的，高度碰撞的，在驱动和耗散尺度之间具有离子趋肤深度，并且能量在磁，热和动力学之间近似均分。 先进的诊断，如法拉第旋转成像，汤姆逊散射和成像折射，将被用来研究从层流到湍流等离子体的过渡。 诊断将用于表征功率谱和间歇性结构的演变以上和以下的离子集肤深度，和一个强加的或自生的平均场在相关的湍流结构的作用。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

This award supports a research program to study the physics of a turbulent plasma in the laboratory. Turbulence exists in the fluids that we experience every day. The unpredictability of turbulence limits our forecasting ability for everything from weather to air travel. Turbulence also exists in plasmas - the hot, ionized gases that make up most of the visible Universe. Plasma turbulence plays an important role in a wide range of astrophysical phenomena, from black hole accretion disks to the interstellar medium, where the heating from turbulence enables the formation of organic molecules which are the building blocks of life. Plasma turbulence also limits the performance of potential future fusion energy reactors. This research program will develop a new platform for producing turbulent plasma in the laboratory and new methods for measuring plasma turbulence. The award also supports a substantial effort to develop an open-access plasma laboratory class, which includes designing, building, and testing laboratory experiments that can be easily reproduced by other instructors. If successful, this effort will strengthen the US STEM workforce by spreading plasma physics instruction to a broader range of educational institutions.Just as hydrodynamic turbulence is built from vortices of fluid motions, magnetized plasma turbulence is built from magnetic islands and current sheets, which serve to transfer the magnetic energy between different spatial scales. This project will use an imploding carbon wire-array Z-pinch, driven by the new PUFFIN generator at the Massachusetts Institute of Technology, as a magnetic island merging platform to generate magnetized plasma turbulence. This magnetized plasma turbulence will be in a previously unexplored regime: sustained, highly collisional, with an ion-skin depth between the driving and dissipative scales, and energy approximately equipartitioned between magnetic, thermal, and kinetic. Advanced diagnostics, such as Faraday rotation imaging, Thomson scattering, and imaging refractometry, will be used to study the transition from a laminar to a turbulent plasma. The diagnostics will serve to characterize the evolution of the power-spectrum and intermittent structures above and below the ion skin depth, and the role of an imposed or self-generated mean-field in correlating turbulent structures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.