埃弗谢德效应（英语：Evershed effect)由英国天文学家约翰·埃弗谢德于1909年发现，从太阳黑子的本影和半影间，有气体向二边水平幅射流。流速距出发点越运，速度越快，气体流的典型速度为1-4Km每秒，达到太阳黑子外边界处突然停止，这种现象称为埃弗谢德效应。此效应对太阳黑子的形成，稳定和动力过程都起重要作用；而且是太阳物理的基本问题之一。因此引起人们对这效应的很大兴趣和祥细观察以及理论研究。

现在关于埃弗谢德效应的理论主要有二大类：

但对其物理机制尚未有统一的认识。

The Evershed effect, named after the British astronomer John Evershed, is the radial flow of gas across the photospheric surface of the penumbra of sunspots from the inner border with the umbra towards the outer edge.

The speed varies from around 1 km/s at the border between the umbra and the penumbra to a maximum of around double this in the middle of the penumbra and falls off to zero at the outer edge of the penumbra. Evershed first detected this phenomenon in January 1909, whilst working at the Kodaikanal Solar Observatory in India, when he found that the spectral lines of sunspots showed doppler shift.