Mechanisms of Giant Pulse Formation and Discharge Mode Transition in Silicon Needle-Plane Gaps

In power electronic devices, silicon-based discharge needles are widely used in electrostatic eliminators due to their semiconductor properties, yet their discharge characteristics under negative voltage remain poorly understood. This study investigates the mode transition mechanisms of silicon needle-plate discharge in short air gaps through systematic experiments and spectral diagnostics. By establishing a silicon needle-plate platform with adjustable electrode spacing, we captured four distinct discharge regimes under increasing voltage: trichel pulse, sawtooth pulse, giant pulse, and glow discharge. During the discharge process, negative ions govern pulse interval time, while dense positive ion layers near the needle tip induce a DC offset, driving continuous ionization and mode transitions. Notably, the giant pulse regime (a unique phenomenon linked to silicon’s semiconductor properties) exhibits intense spatial charge disturbance and a sharp increase in pulse amplitude, accompanied by enhanced N₂ second positive band radiation. In addition, reducing the needle-plate gap amplifies charge generation but narrows the operational voltage range of each regime. These findings reveal fundamental mechanisms of silicon-based discharges and provide critical insights for optimizing electrostatic control systems.