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

职业：脉冲功率驱动磁化湍流中的间歇性和二流体转变

• 批准号: 2339326
• 负责人: Jack Hare
• 金额: $ 85万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-12-01 至 2028-11-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2339326&HistoricalAwards=false
• 关键词: CAREER; Intermittency; Two; Fluid; Transitions

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.

该奖项支持在实验室中研究湍流等离子体物理学的研究项目。湍流存在于我们每天经历的流体中。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，等离子体是构成可见宇宙大部分的高温电离气体。等离子体湍流在广泛的天体物理现象中起着重要作用，从黑洞吸积盘到星际介质，其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聚变能反应堆的性能。该研究项目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获取等离子实验室课程的大量工作，包括设计、构建和测试实验室实验，这些实验可以很容易地被其他教师复制。如果成功，这一努力将通过将等离子体物理教学推广到更广泛的教育机构来加强美国的STEM劳动力。正如流体动力学湍流是由流体运动的涡流构成的一样，磁化等离子体湍流是由磁岛和电流片构成的，它们在不同的空间尺度之间传递磁能。该项目将使用由麻省理工学院的新型PUFFIN发电机驱动的内爆碳线阵列Z-pinch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一种以前未被探索过的状态：持续的，高度碰撞的，在驱动和耗散尺度之间有一个离子皮肤深度，能量在磁性，热和动能之间近似均分。先进的诊断技术，如法拉第旋转成像、汤姆逊散射和成像折射法，将用于研究从层流到湍流等离子体的转变。诊断将用于表征功率谱和间歇结构在离子皮肤深度上下的演变，以及在相关湍流结构中强加或自生成的平均场的作用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。