Fundamental and Applied Plasma Research

该项目将利用过去NSF支持下开发的设备和专业知识，开展基础研究和应用研究的实验和理论结合。基础研究将是异常电流穿透的研究。众所周知，从经典电磁理论和许多实际情况的经验来看，高频交流电流不像直流电流那样均匀地穿透导体，而是被限制在称为“表皮层”的狭窄表面区域。人们普遍认为，这种经典的皮肤效应是一种不可避免的自然规律；这种假设是不正确的，因为趋肤效应是基于欧姆定律的，而欧姆定律不是基本的。事实上，经典的集肤效应只有在欧姆定律的初等形式和对称假设适用时才会发生；这种情况对应于层流扩散的电流穿透。在这里要研究的更复杂的情况下，不对称几何被纳入其中，基本的欧姆定律被更复杂的形式所取代；这些变化允许随机或对流扩散发生，其结果是比层流扩散提供更大的电流穿透。应用研究将包括认真尝试使用磁流体动力等离子体稳定技术来消除钢铁工业使用的电炉中特有的和有害的电弧不稳定性。不可思议的是，这些电炉提供了大约三分之一的美国制造的钢铁

This program will use facilities and expertise developed with past NSF support to embark on a combined experimental and theoretical effort of fundamental and applied research. The fundamental research will be a study of anomalous current penetration. It is well known from classical eletromagnetic theory and also from experience in many practical situations, that high frequency AC currents do not penetrate uniformly through conductors as do DC currents but rather are confined to a narrow suface region called the skin layer. It is widely presumed that this classical skin effect is an unavoidable law of nature; this presumption is incorrect because the skin effect is based on Ohm's law which is not fundamental. In fact, the classical skin effect occurs only when the elementary form of Ohm's law together with a symmetry assumption apply; this situation corresponds to current penetration by laminar diffusion. In the more complicated situations to be studied here, asymmetric geometry is incorporated and the elementary Ohm's law is replaced by a more complex form; these changes allow stochastic or convective diffusion to occur with the consequence of much greater current penetration than provided by laminar diffusion. The applied research will consist of a serious attempt to use magnetohyrodynamic plasma stabilization techniques to eliminate instabilities endemic and injurious to the arcs in electric furnaces used by the steel industry. Paranthetically, these electric furnaces provide approximately one third of the total steel manufactured in the U.S.