ANSYS Maxwell
From their website:
Ansys Maxwell is an EM field solver for electric machines, transformers, wireless charging, permanent magnet latches, actuators and other electric mechanical devices. It solves static, frequency-domain and time-varying magnetic and electric fields. Maxwell also offers specialized design interfaces for electric machines and power converters. https://www.ansys.com/products/electronics/ansys-maxwell
Labs
Maxwell is available under Linux.