Plot of the axial magnetic field on the symmetry axis of a <a href="https://en.wikipedia.org/wiki/Helmholtz_coil" class="extiw" title="w:Helmholtz coil">Helmholtz coil</a> and each of the two current loops it consists of.
<a href="//commons.wikimedia.org/wiki/User:Geek3" title="User:Geek3">Geek3</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>