Structural Receptivity and Electromagnetic Actualization: How Field Relations Become Electricity, Heat, Motion, and Information at the Terminal

This preprint introduces Structural Receptivity as a domain realization of Dynamic Structural Realism for electromagnetic terminals. It asks what an incident field relation becomes once it crosses a terminal boundary, and what structural constraints govern that bifurcation. Maintaining the typed generative-coupling syntax P_sem = I_struct * v_sem, the paper maps DSR onto Maxwellian terminal physics and proposes a reverse-design sequence: choose the organized consequence first, then synthesize the terminal constraint field, then match the incident mode. Five falsifiable protocols (B1–B5) are specified. This record is a conceptual and theoretical preprint. No original experimental dataset is reported. Programmable metasurfaces are identified as a future testing interface. It is Paper 2 of the SBE/DSR programme and cites DSR v1.0 (Zenodo Record 22086468).