碩士生: 張書熏
畢業年分: 2025年7月
論文名稱: 尖端電極對真空陰極誘發脈衝式電漿推進器之電漿羽流分布影響(中文) / The effect of sharp electrodes on the plasma plume distribution vacuum cathode-induced pulsed plasma thrusters (英文)
中文摘要:
脈衝電漿推進器（Pulsed Plasma Thruster, PPT）因具結構簡單、體積小、質量輕及功耗低等優勢，特別適用於CubeSat等小型衛星的長時間任務。然而，傳統PPT於長期運行中點火器易產生碳沉積，導致點火不穩定，進而影響性能與壽命。為改善此問題，本研究結合真空陰極電弧推進器（VCAT）與傳統PPT，研製新型真空陰極誘導脈衝電漿推進器（VAI-PPT）。
研究重點在於探討電極幾何設計對電漿羽流特性的影響。實驗透過快速法拉第杯量測不同角度的離子通量分布與速度，並利用高速攝影機分析羽流的方向性與擴散行為。結果顯示，尖端電極相較於平板電極可提升局部電流密度與電離效率，其中心軸平均離子速度達17.95 km/s，較平板電極（15.82 km/s）提升約13.5%；平均離子通量則分別為14 μC與13 μC，顯示尖端電極有助於集中離子束流。羽流影像亦顯示存在兩種速度分層：中性粒子擴散明顯，而離子則受電場加速並集中於中心軸，呈現高度指向性。
綜合而言，本研究證實尖端電極設計可有效提升羽流集中性與穩定性，增進PPT於CubeSat應用中的可靠性，對小型衛星推進技術之發展具重要參考價值。
英文摘要:
The Pulsed Plasma Thruster (PPT) is a low-power electric propulsion system characterized by its simple structure, compact size, lightweight, and low power consumption, making it particularly suitable for long-duration CubeSat missions. However, conventional PPTs often suffer from carbon deposition on the igniter during extended operation, leading to unstable ignition and reduced lifetime. To address this issue, this study integrates the Vacuum Cathode Arc Thruster (VCAT) with a traditional PPT, resulting in the development of a novel Vacuum Arc-Induced Pulsed Plasma Thruster (VAI-PPT).
This research focuses on the influence of electrode geometry on plasma plume characteristics. Experiments were conducted using a fast-response Faraday cup to measure ion flux distribution and velocity at different angles, complemented by high-speed imaging to analyze plume spatial distribution and directivity. Results show that tip electrodes enhance local current density and ionization efficiency compared with flat electrodes. The average ion velocity along the thruster axis reached 17.95 km/s for the tip electrode, approximately 13.5% higher than the 15.82 km/s measured for the flat electrode. Average ion fluxes at the thruster center were 14 μC and 13 μC, respectively, further demonstrating improved ion beam concentration. Imaging revealed a two-layer plume structure: neutral particles exhibited wider diffusion, whereas ions were strongly accelerated and confined along the central axis, resulting in a highly collimated plume.
In summary, the tip electrode design significantly improves plume collimation and stability, thereby enhancing the reliability of PPTs for CubeSat applications. These findings provide valuable insights into advancing compact and reliable propulsion technologies for small satellites.
