• First hollow tungsten negative pressure arc (HT-NPA) with upward adsorption. • Quantitative design via Magnetic-hollow electrode geometry thresholds. • Active arc stabilization enables defect-free thin-wall manufacturing. This study presents a paradigm shift in arc stability control, moving from passive suppression to active construction, by introducing a transformative Negative Pressure Arc (NPA) welding and Additive Manufacturing (AM) technology. It overcomes the inherent limitations of conventional Positive Pressure Arc (PPA), which destabilize molten pools through repulsive forces. By integrating a Longitudinal Magnetic Field (LMF) with a uniquely designed hollow tungsten electrode, we generate a negative-pressure arc with rotational Adsorption Effects (AE)—termed the Hollow Tungsten Negative Pressure Arc (HT-NPA). Through a coupled electromagnetic-fluid-force multiphysics model, we characterize the fundamental formation thresholds of HT-NPA and analyze its distinctive plasma properties, including arc temperature fields, velocity distributions, pressure gradients, and current density profiles. Our work establishes quantitative mapping relationships between LMF parameters, electrode geometry, process variables, and NPA forces, while identifying critical thresholds for adsorption dominance. Furthermore, we elucidate the formation mechanism of rotational adsorption effects and develop a comprehensive arc design methodology for HT-NPA welding/AM. This work provides a new paradigm for actively stabilizing molten pools in precision manufacturing, achieving the proposed shift from passive suppression to active construction.
Wang et al. (2026) studied this question.