Virtual cathode emission of an annular cold cathode
SCIE
SCOPUS
- Title
- Virtual cathode emission of an annular cold cathode
- Authors
- Park, SD; Kim, JH; Han, J; Yoon, M; Park, SY; Choi, DW; Shin, JW; So, JH
- Date Issued
- 2009-11
- Publisher
- AMER PHYSICAL SOC
- Abstract
- Recent measurement of voltage V and current I of the electron gun of a relativistic klystron amplifier revealed that the resulting current-voltage relationship appeared to differ from the usual Child-Langmuir law (I proportional to V-3/2) especially during the initial period of voltage increase. This paper attempts to explain this deviation by examining the emission mechanism using particle-in-cell simulation. The emission area in the cathode increased stepwise as the applied voltage increased and within each step the current and voltage followed the Child-Langmuir law. The electron emission began when the voltage reached a threshold, and the perveance increased with the emission area. Furthermore, an apparent virtual cathode was formed which was larger than the cathode tip. This occurs because, above a certain voltage, the emission from the edge and the side of the cathode surface dominates the emission from the front-end surface.
- Keywords
- SPACE-CHARGE; BEAM
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/26501
- DOI
- 10.1103/PHYSREVSTAB.12.113502
- ISSN
- 1098-4402
- Article Type
- Article
- Citation
- PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS, vol. 12, no. 11, page. 113502 - 113502, 2009-11
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