Nonradiating sources and anapoles are curious objects from the physics of invisibility that illuminate subtle concepts of fundamental electrodynamics and have promising applications in nanophotonics. The present work shows that a perfectly conducting sphere with a hidden magnetic field is a simple nonradiating electromagnetic source with mechanical excitation and complete internal confinement of electromagnetic energy. It does not require external electromagnetic excitation and is excited by rotation, which induces internal charges and currents with a self-compensating external radiation. The constructed source acts on itself through Lorentz forces emerging from the interaction of charges and currents with electromagnetic fields inside the sphere and, when having a freedom of rotation about the fixed center, exhibits regular precession like a gyroscope. This self-action reveals an internal electromagnetic activity of the perfect nonradiating source, externally inactive and invisible. Neutron stars, these nanospheres of space, can be such natural nonradiating sources when their magnetic fields are buried.

非辐射源和阿纳极子是隐形物理学中的好奇物体，它们阐明了基本电动力学的微妙概念，并在纳米光子学中具有广阔的应用前景。目前的工作表明，具有隐藏磁场的完美导电球体是一种简单的非辐射电磁源，具有机械激励和电磁能的完全内部限制。它不需要外部电磁激励，通过旋转激励，从而感应出内部电荷和电流，并具有自我补偿的外部辐射。所构造的源通过洛伦兹力作用于自身，洛伦兹力是由电荷和电流与球体内电磁场的相互作用产生的，并且当具有绕固定中心的自由旋转时，表现出像陀螺仪一样的规则进动。这种自作用揭示了完美的非辐射源的内部电磁活动，外部不活动且不可见。中子星，这些太空纳米球，当它们的磁场被掩埋时，可以成为天然的非辐射源。