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  2. Ryudo Tsukizaki

Ryudo Tsukizaki

  (月崎 竜童)

Profile Information

Affiliation
Associate Professor, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency
Degree
Ph(Mar, 2013, The University of Tokyo)
Researcher number
70720697
ORCID ID
 https://orcid.org/0000-0002-6265-1672
J-GLOBAL ID
202001010789612597
researchmap Member ID
R000013995

Research Interests

 6

Research Areas

 1

Research History

 7
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Education

 4

Committee Memberships

 3

Awards

 15
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Papers

 72
  • Koki Takagi, Yusuke Yamashita, Ryudo Tsukizaki, Kazutaka Nishiyama, Yoshinori Takao
    Journal of Applied Physics, 135(24), Jun 27, 2024  Peer-reviewed
    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), Jun 1, 2024  Peer-reviewed
    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, May, 2024  Peer-reviewed
  • Takuya Koiso, Yusuke Yamashita, Ryudo Tsukizaki, Kazutaka Nishiyama
    Vacuum, 220 112760-112760, Feb, 2024  Peer-reviewed
  • Ayumu Nono, Takato Morishita, Satoshi Hosoda, Ryudo Tsukizaki, Kazutaka Nishiyama
    Acta Astronautica, 212 130-138, Nov, 2023  Peer-reviewed
  • S. Barquero, K. Tabata, R. Tsukizaki, M. Merino, J. Navarro-Cavallé, K. Nishiyama
    Acta Astronautica, Jul, 2023  Peer-reviewed
  • Yusuke YAMASHITA, Takuya KOISO, Ryudo TSUKIZAKI, Kazutaka NISHIYAMA
    Journal of Evolving Space Activities, 1 21, Jun, 2023  Peer-reviewed
  • Yusuke YAMASHITA, Kana HATTORI, Ryudo TSUKIZAKI, Satoshi HOSODA, Kazutaka NISHIYAMA
    Journal of Evolving Space Activities, 1, Apr, 2023  Peer-reviewed
  • Tetsuya Yokoyama, Kazuhide Nagashima, Izumi Nakai, Edward D Young, Yoshinari Abe, Jérôme Aléon, Conel M O'D Alexander, Sachiko Amari, Yuri Amelin, Ken-Ichi Bajo, Martin Bizzarro, Audrey Bouvier, Richard W Carlson, Marc Chaussidon, Byeon-Gak Choi, Nicolas Dauphas, Andrew M Davis, Tommaso Di Rocco, Wataru Fujiya, Ryota Fukai, Ikshu Gautam, Makiko K Haba, Yuki Hibiya, Hiroshi Hidaka, Hisashi Homma, Peter Hoppe, Gary R Huss, Kiyohiro Ichida, Tsuyoshi Iizuka, Trevor R Ireland, Akira Ishikawa, Motoo Ito, Shoichi Itoh, Noriyuki Kawasaki, Noriko T Kita, Kouki Kitajima, Thorsten Kleine, Shintaro Komatani, Alexander N Krot, Ming-Chang Liu, Yuki Masuda, Kevin D McKeegan, Mayu Morita, Kazuko Motomura, Frédéric Moynier, Ann Nguyen, Larry Nittler, Morihiko Onose, Andreas Pack, Changkun Park, Laurette Piani, Liping Qin, Sara S Russell, Naoya Sakamoto, Maria Schönbächler, Lauren Tafla, Haolan Tang, Kentaro Terada, Yasuko Terada, Tomohiro Usui, Sohei Wada, Meenakshi Wadhwa, Richard J Walker, Katsuyuki Yamashita, Qing-Zhu Yin, Shigekazu Yoneda, Hiroharu Yui, Ai-Cheng Zhang, Harold C Connolly Jr, Dante S Lauretta, Tomoki Nakamura, Hiroshi Naraoka, Takaaki Noguchi, Ryuji Okazaki, Kanako Sakamoto, Hikaru Yabuta, Masanao Abe, Masahiko Arakawa, Atsushi Fujii, Masahiko Hayakawa, Naoyuki Hirata, Naru Hirata, Rie Honda, Chikatoshi Honda, Satoshi Hosoda, Yu-Ichi Iijima, Hitoshi Ikeda, Masateru Ishiguro, Yoshiaki Ishihara, Takahiro Iwata, Kosuke Kawahara, Shota Kikuchi, Kohei Kitazato, Koji Matsumoto, Moe Matsuoka, Tatsuhiro Michikami, Yuya Mimasu, Akira Miura, Tomokatsu Morota, Satoru Nakazawa, Noriyuki Namiki, Hirotomo Noda, Rina Noguchi, Naoko Ogawa, Kazunori Ogawa, Tatsuaki Okada, Chisato Okamoto, Go Ono, Masanobu Ozaki, Takanao Saiki, Naoya Sakatani, Hirotaka Sawada, Hiroki Senshu, Yuri Shimaki, Kei Shirai, Seiji Sugita, Yuto Takei, Hiroshi Takeuchi, Satoshi Tanaka, Eri Tatsumi, Fuyuto Terui, Yuichi Tsuda, Ryudo Tsukizaki, Koji Wada, Sei-Ichiro Watanabe, Manabu Yamada, Tetsuya Yamada, Yukio Yamamoto, Hajime Yano, Yasuhiro Yokota, Keisuke Yoshihara, Makoto Yoshikawa, Kent Yoshikawa, Shizuho Furuya, Kentaro Hatakeda, Tasuku Hayashi, Yuya Hitomi, Kazuya Kumagai, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Hiromichi Soejima, Ayako Suzuki, Toru Yada, Daiki Yamamoto, Kasumi Yogata, Miwa Yoshitake, Shogo Tachibana, Hisayoshi Yurimoto
    Science (New York, N.Y.), 379(6634) eabn7850, Feb 24, 2023  Peer-reviewed
    Carbonaceous meteorites are thought to be fragments of C-type (carbonaceous) asteroids. Samples of the C-type asteroid (162173) Ryugu were retrieved by the Hayabusa2 spacecraft. We measured the mineralogy and bulk chemical and isotopic compositions of Ryugu samples. The samples are mainly composed of materials similar to those of carbonaceous chondrite meteorites, particularly the CI (Ivuna-type) group. The samples consist predominantly of minerals formed in aqueous fluid on a parent planetesimal. The primary minerals were altered by fluids at a temperature of 37° ± 10°C, about [Formula: see text] million (statistical) or [Formula: see text] million (systematic) years after the formation of the first solids in the Solar System. After aqueous alteration, the Ryugu samples were likely never heated above ~100°C. The samples have a chemical composition that more closely resembles that of the Sun's photosphere than other natural samples do.
  • Ryuji Okazaki, Bernard Marty, Henner Busemann, Ko Hashizume, Jamie D Gilmour, Alex Meshik, Toru Yada, Fumio Kitajima, Michael W Broadley, David Byrne, Evelyn Füri, My E I Riebe, Daniela Krietsch, Colin Maden, Akizumi Ishida, Patricia Clay, Sarah A Crowther, Lydia Fawcett, Thomas Lawton, Olga Pravdivtseva, Yayoi N Miura, Jisun Park, Ken-Ichi Bajo, Yoshinori Takano, Keita Yamada, Shinsuke Kawagucci, Yohei Matsui, Mizuki Yamamoto, Kevin Righter, Saburo Sakai, Naoyoshi Iwata, Naoki Shirai, Shun Sekimoto, Makoto Inagaki, Mitsuru Ebihara, Reika Yokochi, Kunihiko Nishiizumi, Keisuke Nagao, Jong Ik Lee, Akihiro Kano, Marc W Caffee, Ryu Uemura, Tomoki Nakamura, Hiroshi Naraoka, Takaaki Noguchi, Hikaru Yabuta, Hisayoshi Yurimoto, Shogo Tachibana, Hirotaka Sawada, Kanako Sakamoto, Masanao Abe, Masahiko Arakawa, Atsushi Fujii, Masahiko Hayakawa, Naoyuki Hirata, Naru Hirata, Rie Honda, Chikatoshi Honda, Satoshi Hosoda, Yu-Ichi Iijima, Hitoshi Ikeda, Masateru Ishiguro, Yoshiaki Ishihara, Takahiro Iwata, Kosuke Kawahara, Shota Kikuchi, Kohei Kitazato, Koji Matsumoto, Moe Matsuoka, Tatsuhiro Michikami, Yuya Mimasu, Akira Miura, Tomokatsu Morota, Satoru Nakazawa, Noriyuki Namiki, Hirotomo Noda, Rina Noguchi, Naoko Ogawa, Kazunori Ogawa, Tatsuaki Okada, Chisato Okamoto, Go Ono, Masanobu Ozaki, Takanao Saiki, Naoya Sakatani, Hiroki Senshu, Yuri Shimaki, Kei Shirai, Seiji Sugita, Yuto Takei, Hiroshi Takeuchi, Satoshi Tanaka, Eri Tatsumi, Fuyuto Terui, Ryudo Tsukizaki, Koji Wada, Manabu Yamada, Tetsuya Yamada, Yukio Yamamoto, Hajime Yano, Yasuhiro Yokota, Keisuke Yoshihara, Makoto Yoshikawa, Kent Yoshikawa, Shizuho Furuya, Kentaro Hatakeda, Tasuku Hayashi, Yuya Hitomi, Kazuya Kumagai, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Hiromichi Soejima, Ayako Iwamae, Daiki Yamamoto, Kasumi Yogata, Miwa Yoshitake, Ryota Fukai, Tomohiro Usui, Harold C Connolly Jr, Dante Lauretta, Sei-Ichiro Watanabe, Yuichi Tsuda
    Science (New York, N.Y.), 379(6634) eabo0431, Feb 24, 2023  Peer-reviewed
    The near-Earth carbonaceous asteroid (162173) Ryugu is expected to contain volatile chemical species that could provide information on the origin of Earth's volatiles. Samples of Ryugu were retrieved by the Hayabusa2 spacecraft. We measured noble gas and nitrogen isotopes in Ryugu samples and found that they are dominated by presolar and primordial components, incorporated during Solar System formation. Noble gas concentrations are higher than those in Ivuna-type carbonaceous (CI) chondrite meteorites. Several host phases of isotopically distinct nitrogen have different abundances among the samples. Our measurements support a close relationship between Ryugu and CI chondrites. Noble gases produced by galactic cosmic rays, indicating a ~5 million year exposure, and from implanted solar wind record the recent irradiation history of Ryugu after it migrated to its current orbit.
  • Hikaru Yabuta, George D Cody, Cécile Engrand, Yoko Kebukawa, Bradley De Gregorio, Lydie Bonal, Laurent Remusat, Rhonda Stroud, Eric Quirico, Larry Nittler, Minako Hashiguchi, Mutsumi Komatsu, Taiga Okumura, Jérémie Mathurin, Emmanuel Dartois, Jean Duprat, Yoshio Takahashi, Yasuo Takeichi, David Kilcoyne, Shohei Yamashita, Alexandre Dazzi, Ariane Deniset-Besseau, Scott Sandford, Zita Martins, Yusuke Tamenori, Takuji Ohigashi, Hiroki Suga, Daisuke Wakabayashi, Maximilien Verdier-Paoletti, Smail Mostefaoui, Gilles Montagnac, Jens Barosch, Kanami Kamide, Miho Shigenaka, Laure Bejach, Megumi Matsumoto, Yuma Enokido, Takaaki Noguchi, Hisayoshi Yurimoto, Tomoki Nakamura, Ryuji Okazaki, Hiroshi Naraoka, Kanako Sakamoto, Harold C Connolly Jr, Dante S Lauretta, Masanao Abe, Tatsuaki Okada, Toru Yada, Masahiro Nishimura, Kasumi Yogata, Aiko Nakato, Miwa Yoshitake, Ayako Iwamae, Shizuho Furuya, Kentaro Hatakeda, Akiko Miyazaki, Hiromichi Soejima, Yuya Hitomi, Kazuya Kumagai, Tomohiro Usui, Tasuku Hayashi, Daiki Yamamoto, Ryota Fukai, Seiji Sugita, Kohei Kitazato, Naru Hirata, Rie Honda, Tomokatsu Morota, Eri Tatsumi, Naoya Sakatani, Noriyuki Namiki, Koji Matsumoto, Rina Noguchi, Koji Wada, Hiroki Senshu, Kazunori Ogawa, Yasuhiro Yokota, Yoshiaki Ishihara, Yuri Shimaki, Manabu Yamada, Chikatoshi Honda, Tatsuhiro Michikami, Moe Matsuoka, Naoyuki Hirata, Masahiko Arakawa, Chisato Okamoto, Masateru Ishiguro, Ralf Jaumann, Jean-Pierre Bibring, Matthias Grott, Stefan Schröder, Katharina Otto, Cedric Pilorget, Nicole Schmitz, Jens Biele, Tra-Mi Ho, Aurélie Moussi-Soffys, Akira Miura, Hirotomo Noda, Tetsuya Yamada, Keisuke Yoshihara, Kosuke Kawahara, Hitoshi Ikeda, Yukio Yamamoto, Kei Shirai, Shota Kikuchi, Naoko Ogawa, Hiroshi Takeuchi, Go Ono, Yuya Mimasu, Kent Yoshikawa, Yuto Takei, Atsushi Fujii, Yu-Ichi Iijima, Satoru Nakazawa, Satoshi Hosoda, Takahiro Iwata, Masahiko Hayakawa, Hirotaka Sawada, Hajime Yano, Ryudo Tsukizaki, Masanobu Ozaki, Fuyuto Terui, Satoshi Tanaka, Masaki Fujimoto, Makoto Yoshikawa, Takanao Saiki, Shogo Tachibana, Sei-Ichiro Watanabe, Yuichi Tsuda
    Science (New York, N.Y.), 379(6634) eabn9057, Feb 24, 2023  Peer-reviewed
    Samples of the carbonaceous asteroid (162173) Ryugu were collected and brought to Earth by the Hayabusa2 spacecraft. We investigated the macromolecular organic matter in Ryugu samples and found that it contains aromatic and aliphatic carbon, ketone, and carboxyl functional groups. The spectroscopic features of the organic matter are consistent with those in chemically primitive carbonaceous chondrite meteorites that experienced parent-body aqueous alteration (reactions with liquid water). The morphology of the organic carbon includes nanoglobules and diffuse carbon associated with phyllosilicate and carbonate minerals. Deuterium and/or nitrogen-15 enrichments indicate that the organic matter formed in a cold molecular cloud or the presolar nebula. The diversity of the organic matter indicates variable levels of aqueous alteration on Ryugu's parent body.
  • Hiroshi Naraoka, Yoshinori Takano, Jason P Dworkin, Yasuhiro Oba, Kenji Hamase, Aogu Furusho, Nanako O Ogawa, Minako Hashiguchi, Kazuhiko Fukushima, Dan Aoki, Philippe Schmitt-Kopplin, José C Aponte, Eric T Parker, Daniel P Glavin, Hannah L McLain, Jamie E Elsila, Heather V Graham, John M Eiler, Francois-Regis Orthous-Daunay, Cédric Wolters, Junko Isa, Véronique Vuitton, Roland Thissen, Saburo Sakai, Toshihiro Yoshimura, Toshiki Koga, Naohiko Ohkouchi, Yoshito Chikaraishi, Haruna Sugahara, Hajime Mita, Yoshihiro Furukawa, Norbert Hertkorn, Alexander Ruf, Hisayoshi Yurimoto, Tomoki Nakamura, Takaaki Noguchi, Ryuji Okazaki, Hikaru Yabuta, Kanako Sakamoto, Shogo Tachibana, Harold C Connolly Jr, Dante S Lauretta, Masanao Abe, Toru Yada, Masahiro Nishimura, Kasumi Yogata, Aiko Nakato, Miwa Yoshitake, Ayako Suzuki, Akiko Miyazaki, Shizuho Furuya, Kentaro Hatakeda, Hiromichi Soejima, Yuya Hitomi, Kazuya Kumagai, Tomohiro Usui, Tasuku Hayashi, Daiki Yamamoto, Ryota Fukai, Kohei Kitazato, Seiji Sugita, Noriyuki Namiki, Masahiko Arakawa, Hitoshi Ikeda, Masateru Ishiguro, Naru Hirata, Koji Wada, Yoshiaki Ishihara, Rina Noguchi, Tomokatsu Morota, Naoya Sakatani, Koji Matsumoto, Hiroki Senshu, Rie Honda, Eri Tatsumi, Yasuhiro Yokota, Chikatoshi Honda, Tatsuhiro Michikami, Moe Matsuoka, Akira Miura, Hirotomo Noda, Tetsuya Yamada, Keisuke Yoshihara, Kosuke Kawahara, Masanobu Ozaki, Yu-Ichi Iijima, Hajime Yano, Masahiko Hayakawa, Takahiro Iwata, Ryudo Tsukizaki, Hirotaka Sawada, Satoshi Hosoda, Kazunori Ogawa, Chisato Okamoto, Naoyuki Hirata, Kei Shirai, Yuri Shimaki, Manabu Yamada, Tatsuaki Okada, Yukio Yamamoto, Hiroshi Takeuchi, Atsushi Fujii, Yuto Takei, Kento Yoshikawa, Yuya Mimasu, Go Ono, Naoko Ogawa, Shota Kikuchi, Satoru Nakazawa, Fuyuto Terui, Satoshi Tanaka, Takanao Saiki, Makoto Yoshikawa, Sei-Ichiro Watanabe, Yuichi Tsuda
    Science (New York, N.Y.), 379(6634) eabn9033, Feb 24, 2023  Peer-reviewed
    The Hayabusa2 spacecraft collected samples from the surface of the carbonaceous near-Earth asteroid (162173) Ryugu and brought them to Earth. The samples were expected to contain organic molecules, which record processes that occurred in the early Solar System. We analyzed organic molecules extracted from the Ryugu surface samples. We identified a variety of molecules containing the atoms CHNOS, formed by methylation, hydration, hydroxylation, and sulfurization reactions. Amino acids, aliphatic amines, carboxylic acids, polycyclic aromatic hydrocarbons, and nitrogen-heterocyclic compounds were detected, which had properties consistent with an abiotic origin. These compounds likely arose from an aqueous reaction on Ryugu's parent body and are similar to the organics in Ivuna-type meteorites. These molecules can survive on the surfaces of asteroids and be transported throughout the Solar System.
  • Takaaki Noguchi, Toru Matsumoto, Akira Miyake, Yohei Igami, Mitsutaka Haruta, Hikaru Saito, Satoshi Hata, Yusuke Seto, Masaaki Miyahara, Naotaka Tomioka, Hope A Ishii, John P Bradley, Kenta K Ohtaki, Elena Dobrică, Hugues Leroux, Corentin Le Guillou, Damien Jacob, Francisco de la Peña, Sylvain Laforet, Maya Marinova, Falko Langenhorst, Dennis Harries, Pierre Beck, Thi H V Phan, Rolando Rebois, Neyda M Abreu, Jennifer Gray, Thomas Zega, Pierre-M Zanetta, Michelle S Thompson, Rhonda Stroud, Kate Burgess, Brittany A Cymes, John C Bridges, Leon Hicks, Martin R Lee, Luke Daly, Phil A Bland, Michael E Zolensky, David R Frank, James Martinez, Akira Tsuchiyama, Masahiro Yasutake, Junya Matsuno, Shota Okumura, Itaru Mitsukawa, Kentaro Uesugi, Masayuki Uesugi, Akihisa Takeuchi, Mingqi Sun, Satomi Enju, Aki Takigawa, Tatsuhiro Michikami, Tomoki Nakamura, Megumi Matsumoto, Yusuke Nakauchi, Masanao Abe, Masahiko Arakawa, Atsushi Fujii, Masahiko Hayakawa, Naru Hirata, Naoyuki Hirata, Rie Honda, Chikatoshi Honda, Satoshi Hosoda, Yu-Ichi Iijima, Hitoshi Ikeda, Masateru Ishiguro, Yoshiaki Ishihara, Takahiro Iwata, Kousuke Kawahara, Shota Kikuchi, Kohei Kitazato, Koji Matsumoto, Moe Matsuoka, Yuya Mimasu, Akira Miura, Tomokatsu Morota, Satoru Nakazawa, Noriyuki Namiki, Hirotomo Noda, Rina Noguchi, Naoko Ogawa, Kazunori Ogawa, Tatsuaki Okada, Chisato Okamoto, Go Ono, Masanobu Ozaki, Takanao Saiki, Naoya Sakatani, Hirotaka Sawada, Hiroki Senshu, Yuri Shimaki, Kei Shirai, Seiji Sugita, Yuto Takei, Hiroshi Takeuchi, Satoshi Tanaka, Eri Tatsumi, Fuyuto Terui, Ryudo Tsukizaki, Koji Wada, Manabu Yamada, Tetsuya Yamada, Yukio Yamamoto, Hajime Yano, Yasuhiro Yokota, Keisuke Yoshihara, Makoto Yoshikawa, Kent Yoshikawa, Ryohta Fukai, Shizuho Furuya, Kentaro Hatakeda, Tasuku Hayashi, Yuya Hitomi, Kazuya Kumagai, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Hiromichi Soejima, Ayako I Suzuki, Tomohiro Usui, Toru Yada, Daiki Yamamoto, Kasumi Yogata, Miwa Yoshitake, Harold C Connolly Jr, Dante S Lauretta, Hisayoshi Yurimoto, Kazuhide Nagashima, Noriyuki Kawasaki, Naoya Sakamoto, Ryuji Okazaki, Hikaru Yabuta, Hiroshi Naraoka, Kanako Sakamoto, Shogo Tachibana, Sei-Ichiro Watanabe, Yuichi Tsuda
    Nature astronomy, 7(2) 170-181, 2023  Peer-reviewed
  • Yusuke Yamashita, Ryudo Tsukizaki, Kazutaka Nishiyama
    Journal of Electric Propulsion, 1(1), Dec, 2022  Peer-reviewedInvited
    Abstract In electron cyclotron resonance (ECR) thrusters, the plasma mode transition is a critical phenomenon because it determines the maximum thrust performance. In ECR ion thrusters, ionization generally occurs in the magnetic confinement region, where electrons are continuously heated by ECR and confined by magnetic mirrors. However, as the flow rate increases, ionization is also observed outside the magnetic confinement region, and this induces the plasma mode transition. In our previous work, two-photon absorption laser-induced fluorescence (TALIF) analysis revealed that the stepwise ionization from the metastable state plays an important role in the ionization process. However, the distribution of the stepwise ionization has not yet been revealed because of the long lifetime of the metastable state. In this study, this distribution was investigated using one experimental and two numerical approaches. First, TALIF was applied to two types of gas injection with clear differences in thrust performance and ground-state neutral density distribution. In the first simulation, the metastable state particle simulation was used to estimate the excitation rate distribution. In the second study, simulations of the electric field of microwaves were used to estimate the contribution of the stepwise ionization to the plasma density. The experimental and numerical results revealed that the stepwise ionization spreads outside the magnetic confinement region because of the diffusion of metastable particles, and this spread induces the plasma mode transition, explaining the difference between the two types of gas injection.
  • Ryuji Okazaki, Yayoi N Miura, Yoshinori Takano, Hirotaka Sawada, Kanako Sakamoto, Toru Yada, Keita Yamada, Shinsuke Kawagucci, Yohei Matsui, Ko Hashizume, Akizumi Ishida, Michael W Broadley, Bernard Marty, David Byrne, Evelyn Füri, Alex Meshik, Olga Pravdivtseva, Henner Busemann, My E I Riebe, Jamie Gilmour, Jisun Park, Ken-Ichi Bajo, Kevin Righter, Saburo Sakai, Shun Sekimoto, Fumio Kitajima, Sarah A Crowther, Naoyoshi Iwata, Naoki Shirai, Mitsuru Ebihara, Reika Yokochi, Kunihiko Nishiizumi, Keisuke Nagao, Jong Ik Lee, Patricia Clay, Akihiro Kano, Marc W Caffee, Ryu Uemura, Makoto Inagaki, Daniela Krietsch, Colin Maden, Mizuki Yamamoto, Lydia Fawcett, Thomas Lawton, Tomoki Nakamura, Hiroshi Naraoka, Takaaki Noguchi, Hikaru Yabuta, Hisayoshi Yurimoto, Yuichi Tsuda, Sei-Ichiro Watanabe, Masanao Abe, Masahiko Arakawa, Atsushi Fujii, Masahiko Hayakawa, Naoyuki Hirata, Naru Hirata, Rie Honda, Chikatoshi Honda, Satoshi Hosoda, Yu-Ichi Iijima, Hitoshi Ikeda, Masateru Ishiguro, Yoshiaki Ishihara, Takahiro Iwata, Kosuke Kawahara, Shota Kikuchi, Kohei Kitazato, Koji Matsumoto, Moe Matsuoka, Tatsuhiro Michikami, Yuya Mimasu, Akira Miura, Tomokatsu Morota, Satoru Nakazawa, Noriyuki Namiki, Hirotomo Noda, Rina Noguchi, Naoko Ogawa, Kazunori Ogawa, Tatsuaki Okada, Chisato Okamoto, Go Ono, Masanobu Ozaki, Takanao Saiki, Naoya Sakatani, Hiroki Senshu, Yuri Shimaki, Kei Shirai, Seiji Sugita, Yuto Takei, Hiroshi Takeuchi, Satoshi Tanaka, Eri Tatsumi, Fuyuto Terui, Ryudo Tsukizaki, Koji Wada, Manabu Yamada, Tetsuya Yamada, Yukio Yamamoto, Hajime Yano, Yasuhiro Yokota, Keisuke Yoshihara, Makoto Yoshikawa, Kent Yoshikawa, Shizuho Furuya, Kentaro Hatakeda, Tasuku Hayashi, Yuya Hitomi, Kazuya Kumagai, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Hiromichi Soejima, Ayako Iwamae, Daiki Yamamoto, Kasumi Yogata, Miwa Yoshitake, Ryota Fukai, Tomohiro Usui, Trevor Ireland, Harold C Connolly Jr, Dante S Lauretta, Shogo Tachibana
    Science advances, 8(46) eabo7239, Nov 18, 2022  Peer-reviewed
  • Motoo Ito, Naotaka Tomioka, Masayuki Uesugi, Akira Yamaguchi, Naoki Shirai, Takuji Ohigashi, Ming-Chang Liu, Richard C. Greenwood, Makoto Kimura, Naoya Imae, Kentaro Uesugi, Aiko Nakato, Kasumi Yogata, Hayato Yuzawa, Yu Kodama, Akira Tsuchiyama, Masahiro Yasutake, Ross Findlay, Ian A. Franchi, James A. Malley, Kaitlyn A. McCain, Nozomi Matsuda, Kevin D. McKeegan, Kaori Hirahara, Akihisa Takeuchi, Shun Sekimoto, Ikuya Sakurai, Ikuo Okada, Yuzuru Karouji, Masahiko Arakawa, Atsushi Fujii, Masaki Fujimoto, Masahiko Hayakawa, Naoyuki Hirata, Naru Hirata, Rie Honda, Chikatoshi Honda, Satoshi Hosoda, Yu-ichi Iijima, Hitoshi Ikeda, Masateru Ishiguro, Yoshiaki Ishihara, Takahiro Iwata, Kosuke Kawahara, Shota Kikuchi, Kohei Kitazato, Koji Matsumoto, Moe Matsuoka, Tatsuhiro Michikami, Yuya Mimasu, Akira Miura, Osamu Mori, Tomokatsu Morota, Satoru Nakazawa, Noriyuki Namiki, Hirotomo Noda, Rina Noguchi, Naoko Ogawa, Kazunori Ogawa, Tatsuaki Okada, Chisato Okamoto, Go Ono, Masanobu Ozaki, Takanao Saiki, Naoya Sakatani, Hirotaka Sawada, Hiroki Senshu, Yuri Shimaki, Kei Shirai, Seiji Sugita, Yuto Takei, Hiroshi Takeuchi, Satoshi Tanaka, Eri Tatsumi, Fuyuto Terui, Ryudo Tsukizaki, Koji Wada, Manabu Yamada, Tetsuya Yamada, Yukio Yamamoto, Hajime Yano, Yasuhiro Yokota, Keisuke Yoshihara, Makoto Yoshikawa, Kent Yoshikawa, Ryota Fukai, Shizuho Furuya, Kentaro Hatakeda, Tasuku Hayashi, Yuya Hitomi, Kazuya Kumagai, Akiko Miyazaki, Masahiro Nishimura, Hiromichi Soejima, Ayako Iwamae, Daiki Yamamoto, Miwa Yoshitake, Toru Yada, Masanao Abe, Tomohiro Usui, Sei-ichiro Watanabe, Yuichi Tsuda
    NATURE ASTRONOMY, 6(10) 1163-+, Oct, 2022  Peer-reviewed
  • Yusuke Yamashita, Ryudo Tsukizaki, Kazutaka Nishiyama
    Vacuum, 200 110962-110962, Jun, 2022  Peer-reviewed
  • Satoshi Hosoda, Kazutaka Nishiyama, Ryudo Tsukizaki
    Hayabusa2 Asteroid Sample Return Mission, 401-414, Apr, 2022  Peer-reviewed
  • S. Tachibana, H. Sawada, R. Okazaki, Y. Takano, K. Sakamoto, Y. N. Miura, C. Okamoto, H. Yano, S. Yamanouchi, P. Michel, Y. Zhang, S. Schwartz, F. Thuillet, H. Yurimoto, T. Nakamura, T. Noguchi, H. Yabuta, H. Naraoka, A. Tsuchiyama, N. Imae, K. Kurosawa, A. M. Nakamura, K. Ogawa, S. Sugita, T. Morota, R. Honda, S. Kameda, E. Tatsumi, Y. Cho, K. Yoshioka, Y. Yokota, M. Hayakawa, M. Matsuoka, N. Sakatani, M. Yamada, T. Kouyama, H. Suzuki, C. Honda, T. Yoshimitsu, T. Kubota, H. Demura, T. Yada, M. Nishimura, K. Yogata, A. Nakato, M. Yoshitake, A. I. Suzuki, S. Furuya, K. Hatakeda, A. Miyazaki, K. Kumagai, T. Okada, M. Abe, T. Usui, T. R. Ireland, M. Fujimoto, T. Yamada, M. Arakawa, H. C. Connolly, A. Fujii, S. Hasegawa, N. Hirata, N. Hirata, C. Hirose, S. Hosoda, Y. Iijima, H. Ikeda, M. Ishiguro, Y. Ishihara, T. Iwata, S. Kikuchi, K. Kitazato, D. S. Lauretta, G. Libourel, B. Marty, K. Matsumoto, T. Michikami, Y. Mimasu, A. Miura, O. Mori, K. Nakamura-Messenger, N. Namiki, A. N. Nguyen, L. R. Nittler, H. Noda, R. Noguchi, N. Ogawa, G. Ono, M. Ozaki, H. Senshu, T. Shimada, Y. Shimaki, K. Shirai, S. Soldini, T. Takahashi, Y. Takei, H. Takeuchi, R. Tsukizaki, K. Wada, Y. Yamamoto, K. Yoshikawa, K. Yumoto, M. E. Zolensky, S. Nakazawa, F. Terui, S. Tanaka, T. Saiki, M. Yoshikawa, S. Watanabe, Y. Tsuda
    Science, 375(6584) 1011-1016, Mar 4, 2022  Peer-reviewed
  • Toru Yada, Masanao Abe, Tatsuaki Okada, Aiko Nakato, Kasumi Yogata, Akiko Miyazaki, Kentaro Hatakeda, Kazuya Kumagai, Masahiro Nishimura, Yuya Hitomi, Hiromichi Soejima, Miwa Yoshitake, Ayako Iwamae, Shizuho Furuya, Masayuki Uesugi, Yuzuru Karouji, Tomohiro Usui, Tasuku Hayashi, Daiki Yamamoto, Ryota Fukai, Seiji Sugita, Yuichiro Cho, Koki Yumoto, Yuna Yabe, Jean-Pierre Bibring, Cedric Pilorget, Vincent Hamm, Rosario Brunetto, Lucie Riu, Lionel Lourit, Damien Loizeau, Guillaume Lequertier, Aurelie Moussi-Soffys, Shogo Tachibana, Hirotaka Sawada, Ryuji Okazaki, Yoshinori Takano, Kanako Sakamoto, Yayoi N. Miura, Hajime Yano, Trevor R. Ireland, Tetsuya Yamada, Masaki Fujimoto, Kohei Kitazato, Noriyuki Namiki, Masahiko Arakawa, Naru Hirata, Hisayoshi Yurimoto, Tomoki Nakamura, Takaaki Noguchi, Hikaru Yabuta, Hiroshi Naraoka, Motoo Ito, Eizo Nakamura, Kentaro Uesugi, Katsura Kobayashi, Tatsuhiro Michikami, Hiroshi Kikuchi, Naoyuki Hirata, Yoshiaki Ishihara, Koji Matsumoto, Hirotomo Noda, Rina Noguchi, Yuri Shimaki, Kei Shirai, Kazunori Ogawa, Koji Wada, Hiroki Senshu, Yukio Yamamoto, Tomokatsu Morota, Rie Honda, Chikatoshi Honda, Yasuhiro Yokota, Moe Matsuoka, Naoya Sakatani, Eri Tatsumi, Akira Miura, Manabu Yamada, Atsushi Fujii, Chikako Hirose, Satoshi Hosoda, Hitoshi Ikeda, Takahiro Iwata, Shota Kikuchi, Yuya Mimasu, Osamu Mori, Naoko Ogawa, Go Ono, Takanobu Shimada, Stefania Soldini, Tadateru Takahashi, Yuto Takei, Hiroshi Takeuchi, Ryudo Tsukizaki, Kent Yoshikawa, Fuyuto Terui, Satoru Nakazawa, Satoshi Tanaka, Takanao Saiki, Makoto Yoshikawa, Sei-ichiro Watanabe, Yuichi Tsuda
    Nature Astronomy, 6(2) 214-220, Feb, 2022  Peer-reviewed
  • Takato Morishita, Ryudo Tsukizaki, Kazutaka Nishiyama, Hitoshi Kuninaka
    Journal of Applied Physics, 131(1) 013301-013301, Jan 7, 2022  Peer-reviewedInvited
  • Kiyoshi Kinefuchi, Daisuke Nakata, Giulio Coral, Suyalatu, Hitoshi Sakai, Ryudo Tsukizaki, Kazutaka Nishiyama
    Review of Scientific Instruments, 92(12) 129902-129902, Dec 1, 2021  Peer-reviewed
  • Kiyoshi Kinefuchi, Daisuke Nakata, Giulio Coral, Suyalatu, Hitoshi Sakai, Ryudo Tsukizaki, Kazutaka Nishiyama
    The Review of scientific instruments, 92(11) 114501-114501, Nov 1, 2021  Peer-reviewed
  • Yusuke Yamashita, Ryudo Tsukizaki, Kazutaka Nishiyama
    Plasma Sources Science and Technology, 30(9) 095023-095023, Sep 1, 2021  Peer-reviewed
  • Yusuke Yamashita, Ryudo Tsukizaki, Koda Daiki, Yoshitaka Tani, Ryo Shirakawa, Kana Hattori, Kazutaka Nishiyama
    Acta Astronautica, 185 179-187, Aug, 2021  Peer-reviewed
  • Ryudo Tsukizaki, Yusuke Yamashita, Kiyoshi Kinefuchi, Kazutaka Nishiyama
    VACUUM, 190, Aug, 2021  Peer-reviewed
  • Giulio Coral, Kiyoshi Kinefuchi, Daisuke Nakata, Ryudo Tsukizaki, Kazutaka Nishiyama, Hitoshi Kuninaka
    Acta Astronautica, 181 14-27, Apr, 2021  Peer-reviewed
  • Kiyoshi Kinefuchi, Shinatora Cho, Tsutomu Fukatsu, Ryudo Tsukizaki, Ikkoh Funaki, Yuya Hirano, Yosuke Tashiro, Taizo Shiiki
    JOURNAL OF PROPULSION AND POWER, 37(2) 223-230, Mar, 2021  Peer-reviewed
  • Masatoshi Chono, Naoji Yamamoto, Ryudo Tsukizaki, Takato Morishita, Kenichi Kubota, Shinatra Cho, Kiyoshi Kinefuchi, Toru Takahashi
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 64(3) 189-192, 2021  Peer-reviewed
  • K. Kitazato, R. E. Milliken, T. Iwata, M. Abe, M. Ohtake, S. Matsuura, Y. Takagi, T. Nakamura, T. Hiroi, M. Matsuoka, L. Riu, Y. Nakauchi, K. Tsumura, T. Arai, H. Senshu, N. Hirata, M. A. Barucci, R. Brunetto, C. Pilorget, F. Poulet, J. P. Bibring, D. L. Domingue, F. Vilas, D. Takir, E. Palomba, A. Galiano, D. Perna, T. Osawa, M. Komatsu, A. Nakato, T. Arai, N. Takato, T. Matsunaga, M. Arakawa, T. Saiki, K. Wada, T. Kadono, H. Imamura, H. Yano, K. Shirai, M. Hayakawa, C. Okamoto, H. Sawada, K. Ogawa, Y. Iijima, S. Sugita, R. Honda, T. Morota, S. Kameda, E. Tatsumi, Y. Cho, K. Yoshioka, Y. Yokota, N. Sakatani, M. Yamada, T. Kouyama, H. Suzuki, C. Honda, N. Namiki, T. Mizuno, K. Matsumoto, H. Noda, Y. Ishihara, R. Yamada, K. Yamamoto, F. Yoshida, S. Abe, A. Higuchi, Y. Yamamoto, T. Okada, Y. Shimaki, R. Noguchi, A. Miura, N. Hirata, S. Tachibana, H. Yabuta, M. Ishiguro, H. Ikeda, H. Takeuchi, T. Shimada, O. Mori, S. Hosoda, R. Tsukizaki, S. Soldini, M. Ozaki, F. Terui, N. Ogawa, Y. Mimasu, G. Ono, K. Yoshikawa, C. Hirose, A. Fujii, T. Takahashi, S. Kikuchi, Y. Takei, T. Yamaguchi, S. Nakazawa, S. Tanaka, M. Yoshikawa, S. Watanabe
    Nature Astronomy, 5(3) 246-250, 2021  Peer-reviewed
  • E. Tatsumi, C. Sugimoto, L. Riu, S. Sugita, T. Nakamura, T. Hiroi, T. Morota, M. Popescu, T. Michikami, K. Kitazato, M. Matsuoka, S. Kameda, R. Honda, M. Yamada, N. Sakatani, T. Kouyama, Y. Yokota, C. Honda, H. Suzuki, Y. Cho, K. Ogawa, M. Hayakawa, H. Sawada, K. Yoshioka, C. Pilorget, M. Ishida, D. Domingue, N. Hirata, S. Sasaki, J. de León, M. A. Barucci, P. Michel, M. Suemitsu, T. Saiki, S. Tanaka, F. Terui, S. Nakazawa, S. Kikuchi, T. Yamaguchi, N. Ogawa, G. Ono, Y. Mimasu, K. Yoshikawa, T. Takahashi, Y. Takei, A. Fujii, Y. Yamamoto, T. Okada, C. Hirose, S. Hosoda, O. Mori, T. Shimada, S. Soldini, R. Tsukizaki, T. Mizuno, T. Iwata, H. Yano, M. Ozaki, M. Abe, M. Ohtake, N. Namiki, S. Tachibana, M. Arakawa, H. Ikeda, M. Ishiguro, K. Wada, H. Yabuta, H. Takeuchi, Y. Shimaki, K. Shirai, N. Hirata, Y. Iijima, Y. Tsuda, S. Watanabe, M. Yoshikawa
    Nature Astronomy, 5(1) 39-45, Jan, 2021  Peer-reviewed
  • Yuto Takei, Takanao Saiki, Yukio Yamamoto, Yuya Mimasu, Hiroshi Takeuchi, Hitoshi Ikeda, Naoko Ogawa, Fuyuto Terui, Go Ono, Kent Yoshikawa, Tadateru Takahashi, Hirotaka Sawada, Chikako Hirose, Shota Kikuchi, Atsushi Fujii, Takahiro Iwata, Satoru Nakazawa, Masahiko Hayakawa, Ryudo Tsukizaki, Satoshi Tanaka, Masanori Matsushita, Osamu Mori, Daiki Koda, Takanobu Shimada, Masanobu Ozaki, Masanao Abe, Satoshi Hosoda, Tatsuaki Okada, Hajime Yano, Takaaki Kato, Seiji Yasuda, Kota Matsushima, Tetsuya Masuda, Makoto Yoshikawa, Yuichi Tsuda
    Astrodynamics, 4(4) 349-375, Dec, 2020  Peer-reviewed
  • Takato Morishita, Ryudo Tsukizaki, Naoji Yamamoto, Kiyoshi Kinefuchi, Kazutaka Nishiyama
    ACTA ASTRONAUTICA, 176 413-423, Nov, 2020  Peer-reviewed
  • Yoshitaka Tani, Yusuke Yamashita, Ryudo Tsukizaki, Kazutaka Nishiyama, Hitoshi Kuninaka
    ACTA ASTRONAUTICA, 176 77-88, Nov, 2020  Peer-reviewed
  • Ryo Shirakawa, Yusuke Yamashita, Daiki Koda, Ryudo Tsukizaki, Yusuke Shimizu, Masahito Tagawa, Kazutaka Nishiyama
    ACTA ASTRONAUTICA, 174 367-376, Sep, 2020  Peer-reviewed
  • Kiyoshi Kinefuchi, Shinatora Cho, Ryudo Tsukizaki
    JOURNAL OF PROPULSION AND POWER, 36(4) 586-592, Jul, 2020  Peer-reviewed
  • T. Morota, S. Sugita, Y. Cho, M. Kanamaru, E. Tatsumi, N. Sakatani, R. Honda, N. Hirata, H. Kikuchi, M. Yamada, Y. Yokota, S. Kameda, M. Matsuoka, H. Sawada, C. Honda, T. Kouyama, K. Ogawa, H. Suzuki, K. Yoshioka, M. Hayakawa, N. Hirata, M. Hirabayashi, H. Miyamoto, T. Michikami, T. Hiroi, R. Hemmi, O. S. Barnouin, C. M. Ernst, K. Kitazato, T. Nakamura, L. Riu, H. Senshu, H. Kobayashi, S. Sasaki, G. Komatsu, N. Tanabe, Y. Fujii, T. Irie, M. Suemitsu, N. Takaki, C. Sugimoto, K. Yumoto, M. Ishida, H. Kato, K. Moroi, D. Domingue, P. Michel, C. Pilorget, T. Iwata, M. Abe, M. Ohtake, Y. Nakauchi, K. Tsumura, H. Yabuta, Y. Ishihara, R. Noguchi, K. Matsumoto, A. Miura, N. Namiki, S. Tachibana, M. Arakawa, H. Ikeda, K. Wada, T. Mizuno, C. Hirose, S. Hosoda, O. Mori, T. Shimada, S. Soldini, R. Tsukizaki, H. Yano, M. Ozaki, H. Takeuchi, Y. Yamamoto, T. Okada, Y. Shimaki, K. Shirai, Y. Iijima, H. Noda, S. Kikuchi, T. Yamaguchi, N. Ogawa, G. Ono, Y. Mimasu, K. Yoshikawa, T. Takahashi, Y. Takei, A. Fujii, S. Nakazawa, F. Terui, S. Tanaka, M. Yoshikawa, T. Saiki, S. Watanabe, Y. Tsuda
    Science, 368(6491) 654-659, May 8, 2020  Peer-reviewed
  • M. Arakawa, T. Saiki, K. Wada, K. Ogawa, T. Kadono, K. Shirai, H. Sawada, K. Ishibashi, R. Honda, N. Sakatani, Y. Iijima, C. Okamoto, H. Yano, Y. Takagi, M. Hayakawa, P. Michel, M. Jutzi, Y. Shimaki, S. Kimura, Y. Mimasu, T. Toda, H. Imamura, S. Nakazawa, H. Hayakawa, S. Sugita, T. Morota, S. Kameda, E. Tatsumi, Y. Cho, K. Yoshioka, Y. Yokota, M. Matsuoka, M. Yamada, T. Kouyama, C. Honda, Y. Tsuda, S. Watanabe, M. Yoshikawa, S. Tanaka, F. Terui, S. Kikuchi, T. Yamaguchi, N. Ogawa, G. Ono, K. Yoshikawa, T. Takahashi, Y. Takei, A. Fujii, H. Takeuchi, Y. Yamamoto, T. Okada, C. Hirose, S. Hosoda, O. Mori, T. Shimada, S. Soldini, R. Tsukizaki, T. Iwata, M. Ozaki, M. Abe, N. Namiki, K. Kitazato, S. Tachibana, H. Ikeda, N. Hirata, N. Hirata, R. Noguchi, A. Miura
    Science, 368(6486), Apr, 2020  Peer-reviewed
  • Tatsuaki Okada, Tetsuya Fukuhara, Satoshi Tanaka, Makoto Taguchi, Takehiko Arai, Hiroki Senshu, Naoya Sakatani, Yuri Shimaki, Hirohide Demura, Yoshiko Ogawa, Kentaro Suko, Tomohiko Sekiguchi, Toru Kouyama, Jun Takita, Tsuneo Matsunaga, Takeshi Imamura, Takehiko Wada, Sunao Hasegawa, Joern Helbert, Thomas G. Mueller, Axel Hagermann, Jens Biele, Matthias Grott, Maximilian Hamm, Marco Delbo, Naru Hirata, Naoyuki Hirata, Yukio Yamamoto, Seiji Sugita, Noriyuki Namiki, Kohei Kitazato, Masahiko Arakawa, Shogo Tachibana, Hitoshi Ikeda, Masateru Ishiguro, Koji Wada, Chikatoshi Honda, Rie Honda, Yoshiaki Ishihara, Koji Matsumoto, Moe Matsuoka, Tatsuhiro Michikami, Akira Miura, Tomokatsu Morota, Hirotomo Noda, Rina Noguchi, Kazunori Ogawa, Kei Shirai, Eri Tatsumi, Hikaru Yabuta, Yasuhiro Yokota, Manabu Yamada, Masanao Abe, Masahiko Hayakawa, Takahiro Iwata, Masanobu Ozaki, Hajime Yano, Satoshi Hosoda, Osamu Mori, Hirotaka Sawada, Takanobu Shimada, Hiroshi Takeuchi, Ryudo Tsukizaki, Atsushi Fujii, Chikako Hirose, Shota Kikuchi, Yuya Mimasu, Naoko Ogawa, Go Ono, Tadateru Takahashi, Yuto Takei, Tomohiro Yamaguchi, Kent Yoshikawa, Fuyuto Terui, Takanao Saiki, Satoru Nakazawa, Makoto Yoshikawa, Seiichiro Watanabe, Yuichi Tsuda
    NATURE, 579(7800) 518-522, Mar, 2020  Peer-reviewed
  • YAMASHITA Yusuke, TANI Yoshitaka, TSUKIZAKI Ryudo, KODA Daiki, NISHIYAMA Kazutaka
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, 18(3) 57-63, 2020  Peer-reviewed
    <p>The authors investigate the discharge chamber of the microwave ion thruster μ10 by using kinetic particle simulation. First, to investigate the plasma phenomena qualitatively, we conduct a particle-in-cell (PIC) simulation model. The simulation results indicate that the distribution of ion density is ring-shaped. To verify the simulation result with the experimental result, the simulation result is compared with the optical emission distribution. In low propellant flow rates, the distribution of ion density agrees with the optical emission distribution. However, in high propellant flow rates, the optical emission distribution is different from simulation results in the waveguide due to the excited neutral particles. In the thruster, the performance strongly depends on the location of injecting the propellant. Hence, to develop the plasma simulation for quantitative comparison with the experiment, the distribution of the neutral density is evaluated by using direct Monte Carlo simulation (DSMC). The results show the neutral density in the waveguide increases corresponding to the ratio of waveguide injection, which indicates that the density is one of the most important parameters for quantitative evaluation with the experiment.</p>
  • Kazutaka Nishiyama, Satoshi Hosoda, Ryudo Tsukizaki, Hitoshi Kuninaka
    ACTA ASTRONAUTICA, 166 69-77, Jan, 2020  Peer-reviewed
  • Ryudo Tsukizaki, Yusuke Yamashita, Kiyoshi Kinefuchi, Kazutaka Nishiyama
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 63(6) 281-283, 2020  Peer-reviewed
  • CHO Shinatora, TSUKIZAKI Ryudo, GOTO Daisuke, MATSUNAGA Yoshiki, KUSAWAKE Hiroaki, WATANABE Hiroki, OHKAWA Yasushi
    Space Solar Power Systems, 5 101-106, 2020  Peer-reviewed
    <p>  Mass and cost of In-space transportation systems are investigated parametrically. Analytical investigation shows the cost-optimum thruster specific impulse is smaller than that of the cost-optimum one. Sensitivity analysis reveals that the specific mass, kg/kW of the power system and propulsion system, has dominant influence on the mass and cost of the orbital transfer system. It is also argued that the GTO to GEO scenario is more mass and cost effective than that of the LEO to GEO one, unless the specific mass is drastically improved than the state-of-the-art.</p>
  • Takato Morishita, Ryudo Tsukizaki, Shunya Morita, Daiki Koda, Kazutaka Nishiyama, Hitoshi Kuninaka
    ACTA ASTRONAUTICA, 165 25-31, Dec, 2019  Peer-reviewed
  • Shunichiro Ide, Daiki Koda, Ryudo Tsukizaki, Kazutaka Nishiyama, Hitoshi Kuninaka
    REVIEW OF SCIENTIFIC INSTRUMENTS, 90(10), Oct, 2019  Peer-reviewed
  • Yusuke Yamashita, Ryudo Tsukizaki, Kiyoshi Kinefuchi, Daiki Koda, Yoshitaka Tani, Kazutaka Nishiyama
    VACUUM, 168, Oct, 2019  Peer-reviewed
  • Kiyoshi Kinefuchi, Yoshio Nunome, Shinatora Cho, Ryudo Tsukizaki, Tat Loon Chng
    ACTA ASTRONAUTICA, 161 382-388, Aug, 2019  Peer-reviewed
  • Y. Yamashita, Y. Tani, R. Tsukizaki, D. Koda, K. Nishiyama
    Physics of Plasmas, 26(7), Jul 1, 2019  Peer-reviewed
  • Daiki Koda, Hitoshi Kuninaka, Ryudo Tsukizaki
    JOURNAL OF PROPULSION AND POWER, 35(3) 565-571, May, 2019  Peer-reviewed
  • Y. Tani, R. Tsukizaki, D. Koda, K. Nishiyama, H. Kuninaka
    Acta Astronautica, 157 425-434, Apr, 2019  Peer-reviewed

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  • J-WAVE, JK Radio Tokyo United, https://www.j-wave.co.jp/original/tokyounited/archives/the-hidden-story/2021/02/19-111253.html, Feb, 2021 TV or radio program
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