MRI Consortium: Development of A Large Plasma Device for Studies of Magnetic Reconnection and Related Phenomena

磁重联是磁场的拓扑重排，是宇宙中各种尺度的爆炸和其他等离子体现象的基础。它也普遍存在于磁化的实验室等离子体中。它的无处不在，也许是其他等离子体现象中首屈一指的，与之相匹配的是对其理解的科学挑战。拟议的磁重联装置（MRD）将是一个多用户、多学科、多机构的仪器，它将为磁重联的受控实验研究开辟新的物理机制，否则在受控实验室环境中是不可用的。MRD将允许获得比目前在专用重联实验中获得的数量级更高的无量纲物理参数，将无量纲电导率提高两个数量级，将无量纲尺寸提高一个数量级。这引入了新的物理学，超越了标准的单重联点模型，这种模型被认为在几乎所有感兴趣的等离子体（太空、太阳、天体物理学、核聚变）中都是活跃和关键的。该仪器将允许研究重连物理中的主要开放性问题：为什么重连如此之快？何时会发生多次重连？它们对重连率有何影响？部分电离如何影响重联？三维几何图形如何改变重连？是什么导致了重连？重联是如何将粒子加速到高能量的？这些问题的进展在其他方面受到阻碍：在空间观测中，现场测量数量很少；在太阳和天体物理观测中，遥感器的空间分辨率有限；在聚变实验室等离子体中，探测器的可及性有限；在专用重联实验中，无量纲物理参数的限制。MRD避免了所有这些限制，提供了一种旨在发现重连物理新见解的新仪器。这个项目的跨学科性在于结合了已知发生磁重联的领域的专业知识。这是在跨越各种空间尺度的领域，从天体物理学到太阳物理学，到磁层物理学，再到实验室等离子体（聚变物理）尺度。在普林斯顿大学、斯沃斯莫尔和惠顿学院等机构进行MRD研究，也将丰富等离子体物理学本科课程。

Magnetic reconnection, the topological rearrangement of magnetic field, underlies a huge range of explosive and other plasma phenomena at all scales in the universe. It is also ubiquitous in magnetized laboratory plasmas. Its ubiquity, perhaps second to no other plasma phenomenon, is matched by the scientific challenge of its understanding.The proposed Magnetic Reconnection Device (MRD) will be a multi-user, multi-disciplinary, multi-institutional instrument that will open up new physics regimes for controlled experimental study of magnetic reconnection, regimes that are otherwise unavailable in a controlled laboratory setting. MRD will allow access to dimensionless physics parameters orders of magnitude beyond that presently obtained in dedicated reconnection experiments, increasing the dimensionless electrical conductivity by two orders of magnitude and the dimensionless size by one order of magnitude. This introduces new physics, beyond the standard single-reconnection-site models, that is believed to be active and crucial in nearly all plasmas of interest (space, solar, astrophysical, fusion). The instrument will allow study of the major open questions in reconnection physics: Why is reconnection so fast? When do multiple reconnections occur and how do they affect the reconnection rate? How does partial ionization affect reconnection? How do 3D geometries alter reconnection? What causes the onset of reconnection? How does reconnection accelerate particles to high energy? Progress in these questions is impeded in other venues: in space observations by the small number of in-situ measurements, in solar and astrophysical observations by the limited spatial resolution of remote sensors, in fusion lab plasmas by limited detector accessibility, and in dedicated reconnection experiments by limitations in dimensionless physics parameters. MRD avoids all these limitations, offering a new instrument designed to discover new insights in reconnection physics. The interdisciplinarity of this project lies in the marriage of expertise from the areas where is magnetic reconnection is known to occur. That is in the areas spanning a wide variety of spatial scales from astrophysics, to solar physics, to magnetospheric physics, and down to laboratory plasma (fusion physics) scales. Undergraduate plasma physics programs will also be enriched by the availability to do research on the MRD at such institutions as Princeton University, and Swarthmore and Wheaton colleges.