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Magnetic Torque Report

The torque is calculated using the Maxwell stress tensor \(\mathbb{T}\) [Pa] given by

\[ \mathbb{T} = \mathbf{B} \otimes \mathbf{H} - \frac{1}{2} \left( \mathbf{B} \cdot \mathbf{H} \right) \mathbb{I} \, . \]

The torque \(\mathbf{T}\) [N \(\cdot\) m] is then given by integrating over the surface \(S\) of the center pole body with

\[ \mathbf{T} = \int_S \mathbf{r} \times (\mathbb{T} \cdot \mathbf{n}) \, dS, \]

where \(\mathbf{r}\) is the position vector, and \(\mathbf{n}\) is the normal along the surface.