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  2. 月崎 竜童

月崎 竜童

ツキザキ リュウドウ  (Ryudo Tsukizaki)

基本情報

所属
国立研究開発法人宇宙航空研究開発機構 宇宙科学研究所 准教授
学位
博士(工学)(2013年3月 東京大学)
研究者番号
70720697
ORCID ID
 https://orcid.org/0000-0002-6265-1672
J-GLOBAL ID
202001010789612597
researchmap会員ID
R000013995

研究キーワード

 6

研究分野

 1

経歴

 7
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学歴

 4

委員歴

 3

受賞

 15
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論文

 72
  • Koki Takagi, Yusuke Yamashita, Ryudo Tsukizaki, Kazutaka Nishiyama, Yoshinori Takao
    Journal of Applied Physics 135(24) 2024年6月27日  査読有り
    Ionic liquid electrospray thrusters represent an alternative propulsion method for spacecraft to conventional plasma propulsion because they do not require plasma generation, which significantly increases the thrust efficiency. The porous emitter thruster has the advantages of simple propellant feeding and multi-site emissions, which miniaturize the thruster size and increase thrust. However, the multi-scale nature, that is, nano- to micrometer-sized menisci on the millimeter-size porous needle tip, makes modeling multi-site emissions difficult, and direct observation is also challenging. This paper proposes a simple model for multi-site emissions, which assumes that the ionic conductivity or ion transport in the porous media determines the ion-emission current. The conductivity was evaluated by comparing the experimental and numerical data based on the model. The results suggest that the ionic conductivity of the porous emitter is suppressed by the ion–pore wall friction stress. Additionally, the model indicates that the emission area expansion on the porous emitter creates the unique curve shape of the current vs voltage characteristics for multi-site emissions.
  • Takato Morishita, Ryudo Tsukizaki, Kazutaka Nishiyama
    AIP Advances 14(6) 2024年6月1日  査読有り
    An understanding of the degradation mechanism of a microwave discharge cathode is the key to extending the lifetime of microwave ion thruster systems. This study investigates the effect of nozzle contamination by sputtered Ag-polytetrafluoroethylene (PTFE) on microwave discharge cathode performance. The current–voltage characteristics were measured for nominal and contaminated (by PTFE spray with 0.2 µm thick or tape with 0.15 mm thick) cathodes. The contamination thickness and area on the nozzle were varied to investigate the characteristic differences. It was confirmed that the anode voltage increased by 20 V or more in the case of the contaminated cathode. The anode voltage was measured for the sputter-contaminated cathode to evaluate the effect of contamination under more realistic conditions. After 630 h of sputter-contamination operation, it is estimated that sputtered particles were deposited to a thickness of 77 µm at most, and the anode voltage increased by 8 V. The results show that the downstream surface of the nozzle is critical for maintaining cathode performance. The insulating coating formed by the sputtered PTFE may interfere with ion absorption and degrade electron emission capability. A theoretical model based on the extended Brophy model supports these results. This study provides important information for the use of PTFE-based materials around ion thrusters.
  • Soichiro Tsuji, Takato Morishita, Ayumu Nono, Ryudo Tsukizaki, Kazutaka Nishiyama
    Acta Astronautica 2024年5月  査読有り
  • Takuya Koiso, Yusuke Yamashita, Ryudo Tsukizaki, Kazutaka Nishiyama
    Vacuum 220 112760-112760 2024年2月  査読有り
  • Ayumu Nono, Takato Morishita, Satoshi Hosoda, Ryudo Tsukizaki, Kazutaka Nishiyama
    Acta Astronautica 212 130-138 2023年11月  査読有り
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MISC

 110

書籍等出版物

 3

担当経験のある科目(授業)

 4

所属学協会

 3

共同研究・競争的資金等の研究課題

 8
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産業財産権

 2

学術貢献活動

 1

メディア報道

 1
  • J-WAVE JK Radio Tokyo United https://www.j-wave.co.jp/original/tokyounited/archives/the-hidden-story/2021/02/19-111253.html 2021年2月 テレビ・ラジオ番組
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