差旋层是内部的辐射层和外面有着较差自转的对流层之间的过渡区域，他位在太阳半径外侧的三分之一处。非常迅速的转速变化导致这个地区有很大的切变。对流带的表面像是一般的流体，有着极区转得较慢，赤道转得较快的较差自转。内部的辐射带展现出固体的转动，可能是因为化石场，通过内部的自转速率大约等同于中纬度的自转速率，级旋转速率介于较慢的级区和较快的赤道之间的速率。来自日震学的最近结果指出，差旋层位于0.7太阳半径处 (从核心量起，表面是1太阳半径)，厚度是0.04太阳半径。这意味着有很大的剪切剖面，这是一种可以形成很大规模磁场的方法。差旋层的几何和宽度在太阳发电机的模型中扮演着重要的角色，经由重叠缠绕微弱的极向场可以创造出非常强大的环形场。差旋层这个专门术语是爱德华·史派格和Jean-Paul Zahn在1992年的一篇论文中新创的，模拟于海洋学的温跃层。

The tachocline is the transition region of the Sun between the radiative interior and the differentially rotating outer convective zone. It is in the outer third of the Sun (by radius). This causes the region to have a very large shear as the rotation rate changes very rapidly. The convective exterior rotates as a normal fluid with differential rotation with the poles rotating slowly and the equator rotating quickly. The radiative interior exhibits solid-body rotation, possibly due to a fossil field. The rotation rate through the interior is roughly equal to the rotation rate at mid-latitudes, i.e. in-between the rate at the slow poles and the fast equator. Recent results from helioseismology indicate that the tachocline is located at a radius of at most 0.70 times the Solar radius (measured from the core, i.e., the surface is at 1 solar radius), with a thickness of 0.04 times the solar radius. This would mean the area has a very large shear profile that is one way that large scale magnetic fields can be formed. The geometry and width of the tachocline plays an important role in models of the solar dynamo by winding up weaker poloidal field to create a much stronger toroidal field. The term tachocline was coined in a paper by Edward Spiegel and Jean-Paul Zahn in 1992 by analogy to the oceanic thermocline.