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单词 Poynting vector
释义

Poynting vector

中文百科

坡印廷矢量

约翰·坡印廷
一个由电池（V）和电阻（R）组成的直流电路，用（S, 蓝）表示在周围空间中的坡印廷矢量的方向，产生其的电场为（E, 红），磁场为（H, 绿）。在电池周围区域坡印廷矢量方向向外，说明流出电池的电能进入了电磁场中；在电阻周围区域该矢量方向向内，说明场的能量流入电阻中。在电池与电阻之间的任何平面 P 上，能流密度朝向电阻的方向。
同轴电缆中的坡印廷矢量，以红色表示。
线偏振圆偏振椭圆偏振电场矢量随着时间（z-轴）流易而演变。电场矢量以黑色粗线表示，它的x-分量、y-分量分别以红色细线、蓝色细线表示。在基部的图样是矢量的矢端随着时间流易对于xy-平面的投射。
在这篇文章内，矢量与标量分别用粗体与斜体显示。例如，位置矢量通常用\mathbf{r}\,\!表示；而其大小则用r\,\!来表示。

坡印廷矢量（英语：Poynting vector），亦称能流密度矢量，其方向为电磁能传递方向，大小为能流密度（单位面积的能量传输速率）。坡印廷矢量的SI单位是瓦特每平方米（W/m）。它是以其发现者约翰·坡印廷（John Henry Poynting）来命名。奥利弗·黑维塞和尼科莱·乌诺夫亦独立发现所谓的坡印廷矢量。

英语百科

Poynting vector 坡印廷向量

Dipole radiation of a dipole vertically in the page showing electric field strength (colour) and Poynting vector (arrows) in the plane of the page.
A DC circuit consisting of a battery (V) and resistor (R), showing the direction of the Poynting vector (S, blue) in the space surrounding it, along with the fields it is derived from; the electric field (E, red) and the magnetic field (H, green). In the region around the battery the Poynting vector is directed outward, indicating power flowing out of the battery into the fields; in the region around the resistor the vector is directed inward, indicating field power flowing into the resistor. Across any plane P between the battery and resistor, the Poynting flux is in the direction of the resistor.
Poynting vector in a coaxial cable, shown in red.
Poynting vector in a static field, where E is the electric field, H the magnetic field, and S the Poynting vector.

In physics, the Poynting vector represents the directional energy flux density (the rate of energy transfer per unit area) of an electromagnetic field. The SI unit of the Poynting vector is the watt per square metre (W/m). It is named after its discoverer John Henry Poynting who first derived it in 1884. Oliver Heaviside and Nikolay Umov also independently discovered the Poynting vector.
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更新时间：2025/6/19 13:50:51