Enhanced UV-assisted pulsed discharges via DC-bias-assisted photoemission from a foam Zn cathode

Seed-electron injection governs the inception and development of UV-assisted pulsed discharges, but it is generally limited by weak photoemission from conventional metal cathodes. In this Letter, a DC bias voltage and a foam Zn cathode are integrated into a UV-assisted pulsed discharge system to regulate pre-pulse photoelectron extraction and negative-charge transport. Photocurrent measurements show that the combined configuration produces a markedly higher photocurrent than either factor alone, indicating a synergistic enhancement of photoelectron extraction and negative-charge transport. This synergistic effect is further reflected in pulsed discharge enhancement, leading to an approximately 285.2% increase in discharge energy relative to the UV-irradiated flat Zn cathode without DC bias. Material characterizations and electric-field simulations suggest that the foam Zn framework has a larger specific surface area, higher UV absorptance, and a stronger local electric field near the cathode. When superimposed with the DC bias, the local electric-field enhancement induced by the foam structure is further strengthened, thereby promoting pre-pulse photoelectron extraction, pre-pulse negative-charge transport, and collection. Consequently, the discharge rapidly evolves from a localized discharge to a stable synchronous multichannel discharge.