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Issue: Inconsistency Between Maxwell Stress Tensor and Lorentz Force Computations

Posted 25 août 2025, 09:57 UTC+2 Electromagnetics Version 6.1 0 Replies

Albert Thema

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I would like to confirm, theoretically, computing the force acting on a wire using the Lorentz force method, the surface integration of the Maxwell stress tensor (MST) over a control volume enclosing the object of interest, and the surface integration of the MST directly over the object’s surface should all yield the same result, correct?

I simulated two cases:

Solenoid

Under a non-uniform background magnetic field, the three methods (Lorentz force, MST over a cuboid control volume, and MST over the wire surface) produced consistent results.

However, under a uniform background magnetic field, the computed results from these three methods do not agree with each other.

Straight wire

For both non-uniform and uniform background magnetic fields, the Lorentz force method and the MST over the wire surface gave nearly identical results.

But the MST over a control volume surface did not match the other two methods.

I would like to confirm whether this discrepancy is expected (e.g., due to numerical or formulation differences) or other factors ? I have reduced the size of mesh but still does not seem to work. Thank you

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