? ? 本文用于糾正網(wǎng)絡(luò)中“廣為流傳”的“渦旋電場不真實(shí)存在”的理解謬誤，“渦旋電場”是真實(shí)存在的。當(dāng)然下面即將寫下的內(nèi)容并不僅限于此。如何界定“渦旋電場”揉燃？又應(yīng)該如何認(rèn)識(shí)它呢？“渦旋電流”又源于什么筋栋，與其相對(duì)的概念“徑向電流”又是指什么炊汤，“渦流”的基本應(yīng)用原理，以及弊攘，“渦旋”這個(gè)詞語的一些擴(kuò)展內(nèi)容抢腐，以上。
? ? How to give "Eddy current" a definition? First we should learn something about the "Vortex electric field", as the Maxwell equation hold (Faraday's law, of course, Ampere's Law, but will not be used in the article), the time-varying magnetic field will induce an electric field, which can be expressed as
,
? ? from which we can easily see that the induced electric field is rotational, ie.
.
? ? This kind of induce field is called "Vortex electric field", and its name means the field is different from the electrostatic field, work will be done if a charge go through a loop in it.
? ? After that, we can say the "Eddy current" is current occured in the closed loop in conductor due to the "Vortex electric field", as figure below, Aluminum plate of induction watt-hour meter is an example of the eddy current.
? ? It is also an important thing to referance "The Vortex electric field is provided by both the magnetic field emit by the eddy current and the magnetic field between the magnet and the current loop changes due to the motion of the non-cutting magnetic line", and it is the reason why "Farady's Law" exist.
? ? In a general way, the experiment of "magnetism of rotation" named by Fran?ois Arago, is the first time "Eddy current" has been discovered as a symbol, but this judgement is, to some extent, inaccurate. From now on, this phenomenon will be called as "Radial electric current".
? ? As shown below, the magnetic field is perpendicular to the page for a half and outside for the other side.
? ? When the copper plate begin to rotate, with , draw out the induceed current gennerated by the law of cutting the magnetic induction line, we can easily get the current, this current, which is due to the motion of cutting the magnetic induction line, is called "Radial electric current", different from "Eddy current" with their different mechanism. (As the graph below)
? ? These knowleges are popular in applications such as solid iron transformer core, (to make the core out of thin laminations parallel to the field to protect Joule heating effect), using the? eddy current (the repulsive effects) in levitation, etc.
? ? Finally, I will give out a new senary of the volcabulary "vortex" in Optoelectronics and Laser, which is about "propagation of higher-order coherent vortices and optical vortices".
? ? 近年襟交，渦旋光束在大氣湍流中的傳輸特性和相干渦旋迈倍、光渦旋的動(dòng)態(tài)演化成為光學(xué)微操控、光量子計(jì)算捣域、光數(shù)據(jù)存儲(chǔ)啼染、量子密碼系統(tǒng)和激光通信等領(lǐng)域的研究熱點(diǎn)宴合。下面給出的是以“LG光束”為例的理論模型。? ? ? ? ? ?
? ? 在空間域中迹鹅，LG 光束在入射面 z=0 處的場分布為
? ? 式中卦洽，
為二維平面矢量；
為 Gauss 部分的束腰寬度斜棚；
為方位角阀蒂；
為締合 Laguerre 多項(xiàng)式；
為拓?fù)浜傻苁矗琲e. 光束中每個(gè)光子攜帶的軌道角動(dòng)量蚤霞；
為徑向指數(shù)， ie. 光束的（n+1）個(gè)徑向節(jié)點(diǎn)义钉， Gauss 光束以及 Gauss 渦旋光束都是其特殊情況昧绣。
? ? 利用廣義 Huygens-Fresnel 原理，并調(diào)用謝爾相關(guān)項(xiàng)進(jìn)行計(jì)算捶闸，最終可以得到LG光束在大氣湍流中的交叉譜密度函數(shù)的解析表達(dá)式為
? ? 其中滞乙，
為輸出平面的兩點(diǎn)，而
為復(fù)雜積分帶來的幾何系數(shù)鉴嗤。
? ? 根據(jù)光譜相干度定義，可以得出相干渦旋位置所滿足的方程組：
,
? ?
定義為相干度
.
? ? ? ? ————Journal of Optoelectronics . Laser Vol.27 No.7 July 2016
