In Electromagnetism, the field pattern of a magnetic field inside the toroid is _______.

Magnetic Field of Toroid

The magnetic field in the core of the toroid is non-uniform because inside a coil has the shape of a torus whose mirror radius is much smaller than the length of the central circle.

Consider a hollow circular ring with many turns of the current-carrying wire that is wound around it. In the above figure, let the magnetic field, B be present at point P which is inside the toroid.

In the above figure, the loop is considered as an Amperian loop that forms a circle through point P resulting in concentric circles inside the toroid.

Due to the symmetric field, the magnitude at all the points in the circle is equal, and the field is tangential.

Using Ampere law:

\(\oint B.dl=\mu_oNI\)

\(2\pi rB=\mu_oNI\)

\(B={\mu_oNI\over 2\pi r}\)

Therefore, we can conclude that the magnetic field B varies and is not uniform over the cross-section.