Magnetic Flux

磁通量

Magnetic flux is the product of the average magnetic field times the perpendicular area that it penetrates. It is a quantity of convenience in the statement of Faraday's Law and in the discussion of objects like transformers and solenoids. In the case of an electric generator where the magnetic field penetrates a rotating coil, the area used in defining the flux is the projection of the coil area onto the plane perpendicular to the magnetic field. Since the SI unit for magnetic field is the Tesla, the unit for magnetic flux would be Tesla m². This unit combination has the historical name Weber (Wb).

磁通量是平均磁场与它穿透的垂直面积的乘积。它是表述法拉第定律和讨论变压器及螺线管等物体时的方便量。在电动发电机的情况下，当磁场穿透一个旋转的线圈时，用于定义磁通量的面积是线圈面积在垂直于磁场平面上的投影。由于SI单位中磁场的单位是特斯拉，因此磁通量的单位就是特斯拉平方米。这种单位组合有历史名称韦伯（Wb）。

Magnetic Flux Illustrations

磁通量示意图

The contribution to magnetic flux for a given area is equal to the area times the component of magnetic field perpendicular to the area. For a closed surface, the sum of magnetic flux is always equal to zero (Gauss' law for magnetism). No matter how small the volume, the magnetic sources are always dipole sources (like miniature bar magnets), so that there are as many magnetic field lines coming in (to the south pole) as out (from the north pole).

给定面积的磁通量等于面积与该面积法线方向上磁感应强度的乘积。对于闭合曲面，磁通量的总和总是等于零（磁通量的高斯定律）。无论体积多小，磁源总是偶极子源（如同小磁铁），因此进入的磁感线数量（指向南极）与离开的数量（来自北极）相等。