Anomalous Heat Effects via Longitudinal and Transversal Excitations in Constantan Wires: Advances in Electromigration and Plasma Generation

We present an integrated set of experiments that advance the long-standing search for Anomalous Heat Effects (AHE) in metal–hydrogen systems, with a decisive shift toward inexpensive materials and dynamic drive conditions. Our working medium is commercial Constantan wire (Cu55Ni44Mn1), selected in 2011 to replace palladium due to its lower cost and higher defect density. The wire is operated in a compact INFN-LNF reactor that reaches internal temperatures of 900 C, while the external jacket remains below 350 C. The wire is simultaneously excited in two orthogonal modes: (i) high-density axial current pulses that drive thermionic emission, electromigration, and the characteristic “wire-breathing” pressure wave; and (ii) a transverse plasma, generated either as a Paschen spark or, more desirably, as a self-quenching dielectric-barrier discharge (DBD) stabilized by a Ca/Sr/Ba low-work-function coating, analogous to those employed in thermionic valve cathodes. Custom dimmer-based power electronics (50 Hz mains frequency, 90–95% efficiency) allow real-time adjustment of fall time (with rise time <1 µs), duty cycle, and polarity. Embedded K-type thermocouples provide in-situ calorimetry accurate to ±1 W. In a 50% H2–50% Ar atmosphere at 200 mbar, direct-current operation serves as the “null” line. Pulsed driving lifts the thermal baseline, and adding a pulsed counter-electrode (CE) increases net excess heat to 20–21 W for an 80 W input (peak COP ⇡ 1.27 at 60 W). Reducing the pressure to 140 mbar and enlarging the CE coupling capacitor maintains Paschen/DBD activity and yields comparable—or slightly enhanced—AHE, despite incurring an additional 4–5 W of circuit losses. After two weeks of dormancy, the effect diminishes but can be partially recovered through in-situ redox cycling and extended pulsing, consistent with the involvement of metastable vacancy clusters anticipated by the Fukai–Staker super-loading model. Thermionic emission and electromigration show a strong correlation with excess heat generation, in agreement with Preparata’s coherence framework. Future work will investigate tungsten–NiCu multilayer electrodes driven by SiC pulse electronics, complemented by fast optical and X-ray diagnostics to resolve sub-millisecond dynamics. The reproducibility achieved here—using only commodity components—underscores the potential of Constantan-based AHE modules for high-temperature process heat, lightweight aerospace power systems, and distributed micro-grid applications.