Numerical Simulations and Theoretical Studies of the Plasma Dynamo and Couette Flow Experiment

该奖项资助开展数值模拟以支持等离子体发电机和Couette流动实验的研究。首次建立了等离子体Couette实验来研究高温、非磁化和快速流动等离子体中的磁致旋转不稳定性(MRI)。等离子体受到等离子体表面强多极磁场的限制。该实验的目的是研究核磁共振以及在高雷诺数(适用于天体物理等离子体的区域)下由核磁共振驱动的湍流可能产生的磁场。如果成功，这个概念可以很容易地扩展到更大的、基于等离子体的发电机实验，研究磁场的自我产生(MHD发电机)，但通过受限等离子体中的流体动力学驱动的湍流。数值模拟和理论研究对于加深对这两个实验的理解并确保其最终成功是至关重要的。使用扩展的MHD程序Nimrod进行数值模拟，并将数值结果与实验测量结果直接进行比较。数值模拟也有望为实验设计提供指导。用Nimrod程序进行的模拟将对磁融合社区广泛使用的Nimrod程序的验证大有裨益。此外，磁旋转不稳定性(MRI)被认为在许多天体物理环境中起着至关重要的作用。因此，有必要进行一系列物理实验和计算模型，以测试、指导甚至挑战目前应用于与磁共振相关的理论模型中的许多戒律。该提案已提交给NSF-美国能源部等离子体科学与工程伙伴关系联合征集08-589。该奖项由数学和物理科学局的物理和天文科学部联合资助。

This award funds research to carry out numerical simulations in support of Plasma Dynamo and Couette Flow experiments. A Plasma Couette experiment, the first of its kind, has been constructed to study Magnetorotational Instability (MRI) in a hot, unmagnetized and fast flowing plasma. Plasma is confined by a strong multipole magnetic field at the plasma surface. The goals of the experiment are to study the MRI and possible self-generation of magnetic field by MRI-driven turbulence at high magnetic Reynolds numbers (the regime applicable to astrophysical plasmas). If successful, the concept could be readily extended to a larger, plasma-based dynamo experiment, studying the self-generation of magnetic field (MHD dynamo) but through hydrodynamic-driven turbulence in a confined plasma. Numerical modeling and theoretical studies are crucial for advancing the understanding of these two experiments and assuring their ultimate success. Numerical simulations using the extended MHD code, NIMROD, will be done and the numerical results will be directly compared with the experimental measurements. Numerical simulations are also expected to provide a guidance for the experimental design.The proposed simulations with NIMROD code would strongly benefit the validation of a code, NIMROD, extensively used by the Magnetic Fusion community. In addition, the Magneto-rotational Instability (MRI) is thought to play a vital role in many astrophysical settings. Thus it is essential to have a line of physical experiments and computational models carried out that can test, guide and perhaps challenge many of the precepts now being applied in theoretical models with regard to MRI. This proposal was submitted to the NSF-DoE Partnership in Plasma Science and Engineering joint solicitation 08-589. This award is being funded jointly by the Divisions of Physics and Astronomical Sciences of the Mathematical and Physical Sciences Directorate.