In this paper,a high-precision electromagnetic measurement system suitable for a hightemperature and high-speed plasma is built to provide a platform for scientific research on the interaction mechanism of the electro...In this paper,a high-precision electromagnetic measurement system suitable for a hightemperature and high-speed plasma is built to provide a platform for scientific research on the interaction mechanism of the electromagnetic fields and a plasma.This paper presents a method to measure the electromagnetic field inside a plasma by using a probe and Poynting vector conversion,which is a new and completely different method from the traditional method of measuring the electromagnetic field inside plasma.In addition,for this system and method,this work designs a microstrip antenna probe that can suppress multipath effects.This method is confirmed to be valid and usable after closed-loop verification by the CST software.展开更多
We study the controversy about the proper determination of the electromagnetic energy-flux field in anisotropic materials, which has been revived due to the relatively recent experiments on negative refraction in meta...We study the controversy about the proper determination of the electromagnetic energy-flux field in anisotropic materials, which has been revived due to the relatively recent experiments on negative refraction in metamaterials. Rather than analyzing energy-balance arguments, we use a pragmatic approach inspired by geometrical optics, and compare the predictions on angles of refraction at a flat interface of two possible choices on the energy flux: and . We carry out this comparison for a monochromatic Gaussian beam propagating in an anisotropic non-dissipative anisotropic metamaterial, in which the spatial localization of the electromagnetic field allows a more natural assignment of directions, in contrast to the usual study of plane waves. We compare our approach with the formalism of geometrical optics, which we generalize and analyze numerically the consequences of either choice.展开更多
近年来随着石油资源的持续紧张,使得探明更多石油资源储量变的迫在眉睫,目前的油气勘探已经从常规油气转向了非常规油气勘探,那么如何提高成像精度就变的越发重要,现如今基于双程波动方程的叠前逆时偏移方法在地震资料成像领域吸引了越...近年来随着石油资源的持续紧张,使得探明更多石油资源储量变的迫在眉睫,目前的油气勘探已经从常规油气转向了非常规油气勘探,那么如何提高成像精度就变的越发重要,现如今基于双程波动方程的叠前逆时偏移方法在地震资料成像领域吸引了越来越多地球物理专家的关注,逆时偏移方法相对于K i r c h h o ff偏移和单程波波动方程偏移方法,具有原理简单、成像精确且无倾角限制、适应任意复杂速度模型等诸多优点。但是低频噪声的存在严重影响了成像的质量。Poynting矢量的方向代表了介质中地震波的传播方向,根据Poynting矢量将地震波场分离成上行波、下行波。再把同方向的上下行波进行互相关成像,相对比与常规互相关成像条件,该方法简单易行,所需额外的计算量和存储量都极小,将该方法用在M a r m o u s i模型上,得到的偏移成像结果显示低频噪声都得到了很好的压制。展开更多
基金supported by National Natural Science Foundation of China(No.61627901)。
文摘In this paper,a high-precision electromagnetic measurement system suitable for a hightemperature and high-speed plasma is built to provide a platform for scientific research on the interaction mechanism of the electromagnetic fields and a plasma.This paper presents a method to measure the electromagnetic field inside a plasma by using a probe and Poynting vector conversion,which is a new and completely different method from the traditional method of measuring the electromagnetic field inside plasma.In addition,for this system and method,this work designs a microstrip antenna probe that can suppress multipath effects.This method is confirmed to be valid and usable after closed-loop verification by the CST software.
文摘We study the controversy about the proper determination of the electromagnetic energy-flux field in anisotropic materials, which has been revived due to the relatively recent experiments on negative refraction in metamaterials. Rather than analyzing energy-balance arguments, we use a pragmatic approach inspired by geometrical optics, and compare the predictions on angles of refraction at a flat interface of two possible choices on the energy flux: and . We carry out this comparison for a monochromatic Gaussian beam propagating in an anisotropic non-dissipative anisotropic metamaterial, in which the spatial localization of the electromagnetic field allows a more natural assignment of directions, in contrast to the usual study of plane waves. We compare our approach with the formalism of geometrical optics, which we generalize and analyze numerically the consequences of either choice.
文摘近年来随着石油资源的持续紧张,使得探明更多石油资源储量变的迫在眉睫,目前的油气勘探已经从常规油气转向了非常规油气勘探,那么如何提高成像精度就变的越发重要,现如今基于双程波动方程的叠前逆时偏移方法在地震资料成像领域吸引了越来越多地球物理专家的关注,逆时偏移方法相对于K i r c h h o ff偏移和单程波波动方程偏移方法,具有原理简单、成像精确且无倾角限制、适应任意复杂速度模型等诸多优点。但是低频噪声的存在严重影响了成像的质量。Poynting矢量的方向代表了介质中地震波的传播方向,根据Poynting矢量将地震波场分离成上行波、下行波。再把同方向的上下行波进行互相关成像,相对比与常规互相关成像条件,该方法简单易行,所需额外的计算量和存储量都极小,将该方法用在M a r m o u s i模型上,得到的偏移成像结果显示低频噪声都得到了很好的压制。
