Xin Li , Tianhang Meng , Zhongxi Ning , Hui Liu , Chao Sun , Yang Liu , Stepan I. Eliseev , Daren Yu
{"title":"碘LaB6空心阴极的振荡","authors":"Xin Li , Tianhang Meng , Zhongxi Ning , Hui Liu , Chao Sun , Yang Liu , Stepan I. Eliseev , Daren Yu","doi":"10.1016/j.vacuum.2025.114744","DOIUrl":null,"url":null,"abstract":"<div><div>Iodine-fed electric propulsion systems have achieved significant technological progress in recent years, the operating range of these systems remains fundamentally limited by ampere level iodine compatible hollow cathode technology. Preliminary studies on discharge characteristics have found that LaB<sub>6</sub> hollow cathode is a potential strategy. In this study, a conventional LaB<sub>6</sub> hollow cathode made with iodine-resistant materials was designed and tested in an iodine-compatible vacuum facility. The waveform, bispectral characteristics, and dispersion relation of the iodine hollow cathode were obtained and compared with the estimated collision reaction frequency. We analyzed the potential reaction processes both inside and outside the cathode and assessed how oscillation affects the lifetime of the iodine hollow cathode. The results indicate that the chaotic low-frequency oscillations were the main oscillation mode affecting the performance of the iodine cathode, involving multiple reaction processes that interfere with each other. The oscillation inside the cathode was mainly affected by vibrational excitation and iodine molecular ionization, while the oscillation outside the cathode was affected primarily by processes such as neutral gas flow, excitation, ionization, dissociation, and ion transit-time instability. The overall oscillation of iodine cathode is a non-dominant unstable mode with uniform energy distribution. A single 27-h self-sustaining experiment found that low-frequency oscillation has a significant impact on the emitter and the orifice, thereby reducing the cathode lifetime. The main reaction process inside and outside the iodine cathode and the influence relationship between the reactions were understood by the oscillation characteristics. It provides a theoretical basis to improve the performance of the iodine hollow cathode in the future.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"242 ","pages":"Article 114744"},"PeriodicalIF":3.9000,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Oscillations of iodine LaB6 hollow cathode\",\"authors\":\"Xin Li , Tianhang Meng , Zhongxi Ning , Hui Liu , Chao Sun , Yang Liu , Stepan I. Eliseev , Daren Yu\",\"doi\":\"10.1016/j.vacuum.2025.114744\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Iodine-fed electric propulsion systems have achieved significant technological progress in recent years, the operating range of these systems remains fundamentally limited by ampere level iodine compatible hollow cathode technology. Preliminary studies on discharge characteristics have found that LaB<sub>6</sub> hollow cathode is a potential strategy. In this study, a conventional LaB<sub>6</sub> hollow cathode made with iodine-resistant materials was designed and tested in an iodine-compatible vacuum facility. The waveform, bispectral characteristics, and dispersion relation of the iodine hollow cathode were obtained and compared with the estimated collision reaction frequency. We analyzed the potential reaction processes both inside and outside the cathode and assessed how oscillation affects the lifetime of the iodine hollow cathode. The results indicate that the chaotic low-frequency oscillations were the main oscillation mode affecting the performance of the iodine cathode, involving multiple reaction processes that interfere with each other. The oscillation inside the cathode was mainly affected by vibrational excitation and iodine molecular ionization, while the oscillation outside the cathode was affected primarily by processes such as neutral gas flow, excitation, ionization, dissociation, and ion transit-time instability. The overall oscillation of iodine cathode is a non-dominant unstable mode with uniform energy distribution. A single 27-h self-sustaining experiment found that low-frequency oscillation has a significant impact on the emitter and the orifice, thereby reducing the cathode lifetime. The main reaction process inside and outside the iodine cathode and the influence relationship between the reactions were understood by the oscillation characteristics. It provides a theoretical basis to improve the performance of the iodine hollow cathode in the future.</div></div>\",\"PeriodicalId\":23559,\"journal\":{\"name\":\"Vacuum\",\"volume\":\"242 \",\"pages\":\"Article 114744\"},\"PeriodicalIF\":3.9000,\"publicationDate\":\"2025-09-13\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Vacuum\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0042207X25007341\",\"RegionNum\":2,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MATERIALS SCIENCE, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Vacuum","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0042207X25007341","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
Iodine-fed electric propulsion systems have achieved significant technological progress in recent years, the operating range of these systems remains fundamentally limited by ampere level iodine compatible hollow cathode technology. Preliminary studies on discharge characteristics have found that LaB6 hollow cathode is a potential strategy. In this study, a conventional LaB6 hollow cathode made with iodine-resistant materials was designed and tested in an iodine-compatible vacuum facility. The waveform, bispectral characteristics, and dispersion relation of the iodine hollow cathode were obtained and compared with the estimated collision reaction frequency. We analyzed the potential reaction processes both inside and outside the cathode and assessed how oscillation affects the lifetime of the iodine hollow cathode. The results indicate that the chaotic low-frequency oscillations were the main oscillation mode affecting the performance of the iodine cathode, involving multiple reaction processes that interfere with each other. The oscillation inside the cathode was mainly affected by vibrational excitation and iodine molecular ionization, while the oscillation outside the cathode was affected primarily by processes such as neutral gas flow, excitation, ionization, dissociation, and ion transit-time instability. The overall oscillation of iodine cathode is a non-dominant unstable mode with uniform energy distribution. A single 27-h self-sustaining experiment found that low-frequency oscillation has a significant impact on the emitter and the orifice, thereby reducing the cathode lifetime. The main reaction process inside and outside the iodine cathode and the influence relationship between the reactions were understood by the oscillation characteristics. It provides a theoretical basis to improve the performance of the iodine hollow cathode in the future.
期刊介绍:
Vacuum is an international rapid publications journal with a focus on short communication. All papers are peer-reviewed, with the review process for short communication geared towards very fast turnaround times. The journal also published full research papers, thematic issues and selected papers from leading conferences.
A report in Vacuum should represent a major advance in an area that involves a controlled environment at pressures of one atmosphere or below.
The scope of the journal includes:
1. Vacuum; original developments in vacuum pumping and instrumentation, vacuum measurement, vacuum gas dynamics, gas-surface interactions, surface treatment for UHV applications and low outgassing, vacuum melting, sintering, and vacuum metrology. Technology and solutions for large-scale facilities (e.g., particle accelerators and fusion devices). New instrumentation ( e.g., detectors and electron microscopes).
2. Plasma science; advances in PVD, CVD, plasma-assisted CVD, ion sources, deposition processes and analysis.
3. Surface science; surface engineering, surface chemistry, surface analysis, crystal growth, ion-surface interactions and etching, nanometer-scale processing, surface modification.
4. Materials science; novel functional or structural materials. Metals, ceramics, and polymers. Experiments, simulations, and modelling for understanding structure-property relationships. Thin films and coatings. Nanostructures and ion implantation.