Faculty Profiles - OYAMA, Shin-ichiro

Papers - OYAMA, Shin-ichiro

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Observations of fragmented aurora-like emissions and picket fence on the poleward edge of the auroral oval Open Access

Nanjo, S; Herlingshaw, K; Sergienko, T; Cessateur, G; Partamies, N; Johnsen, M; Hosokawa, K; Lamy, H; Ogawa, Y; Kero, A; Oyama, SI; Yamauchi, M

ANNALES GEOPHYSICAE Vol. 44 ( 1 ) page： 63 - 84 2026.2

Ionosphere-Thermosphere Coupling in the Northern Polar Region During the May 2024 Geomagnetic Superstorm Open Access

Cai, L; Aikio, A; Geethakumari, GP; Vanhamäki, H; Virtanen, II; Oyama, S; Zhang, YL; Zhang, JJ; Hairston, M

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 131 ( 2 ) 2026.2

Electron-driven variability of the upper-atmospheric nitric oxide column density over the Syowa station in Antarctica Open Access

Verronen, P; Mizuno, A; Miyoshi, Y; Kumar, S; Nakajima, T; Oyama, SI; Nagahama, T; Nozawa, S; Szelag, M; Häkkilä, T; Kalakoski, N; Kero, A; Turunen, E; Kasahara, S; Yokota, S; Keika, K; Hori, T; Mitani, T; Takashima, T; Shinohara, I

ANNALES GEOPHYSICAE Vol. 43 ( 2 ) page： 561 - 578 2025.10

Geomagnetic Activity Dependence of the Auroral Electron Precipitation Spectrum at High Latitudes Open Access

Oyama, S; Virtanen, II; Tesfaw, HW; Raita, T; Holappa, L; Miyoshi, Y; Cai, L; Vanhamäki, H; Aikio, AT; Ogawa, Y; Hosokawa, K

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 130 ( 9 ) 2025.9

Multi-Event Analysis of STEVE, SAR Arc, and Red/Green Arc at Subauroral Latitudes Using Data From Ground Optical and Radio Instruments and the Arase and Van Allen Probes Satellites Open Access

Sugimura, R; Shiokawa, K; Otsuka, Y; Oyama, S; Oksanen, A; Connors, M; Kadokura, A; Poddelsky, I; Nishitani, N; Shepherd, SG; Ruohoniemi, JM; Smith, C; Spence, H; Reeves, G; Funsten, HO; Miyoshi, Y; Shinohara, I; Kasahara, Y; Tsuchiya, F; Kumamoto, A; Shinbori, A; Asamura, K; Yokota, S; Kazama, Y; Jun, CW; Wang, SY; Tam, SWY; Chang, TF; Wang, BJ; Kasahara, S; Keika, K; Hori, T; Matsuoka, A

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 130 ( 2 ) 2025.2

Total Electron Content Variations During an HSS/SIR-Driven Geomagnetic Storm at High and Mid Latitudes Open Access

Geethakumari, GP; Aikio, AT; Cai, L; Vanhamäki, H; Virtanen, II; Coster, A; Marchaudon, A; Blelly, PL; Maute, A; Norberg, J; Oyama, S; Zhang, Y; Kunduri, BSR

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 129 ( 12 ) 2024.12

EISCAT Observations of Depleted High-Latitude <i>F</i>-Region During an HSS/SIR-Driven Magnetic Storm Open Access

Ellahouny, NM; Aikio, AT; Vanhamäki, H; Virtanen, II; Cai, L; Marchaudon, A; Blelly, PL; Coster, A; Norberg, J; Maute, A; Oyama, S

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 129 ( 9 ) 2024.9

Development and Evaluation of a Comprehensive Machine Learning Tool Differentiating Idiopathic Pulmonary Fibrosis from Other Interstitial Lung Diseases in the Japanese nationwide registry (PROMISE study)

Furukawa, T; Kondoh, Y; Oyama, S; Yokota, H; Teramachi, R; Hozumi, H; Shiratori, Y; Hasegawa, Y; Suda, T; Ishii, M

EUROPEAN RESPIRATORY JOURNAL Vol. 64 2024.9

Observational Evidence for Three Time-Scale Modulations in the Pulsating Aurora Open Access

Chen, R; Miyoshi, Y; Gao, XL; Lu, QM; Tsurutani, BT; Hosokawa, K; Hori, T; Ogawa, Y; Oyama, SI; Kasahara, Y; Matsuda, S; Nakamura, S; Matsuoka, A; Shinohara, I

GEOPHYSICAL RESEARCH LETTERS Vol. 51 ( 16 ) 2024.8

Effect of Polar Cap Patches on the High-Latitude Upper Thermospheric Winds Open Access

Cai, L; Aikio, A; Oyama, S; Ivchenko, N; Vanhamäki, H; Virtanen, I; Buchert, S; Mekuriaw, ML; Zhang, Y

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 129 ( 8 ) 2024.7

Spatiotemporal Development of Cosmic Noise Absorption at Subauroral Latitudes Using Multipoint Ground-Based Riometers Open Access

Kato, Y; Shiokawa, K; Tanaka, Y; Ozaki, M; Kadokura, A; Oyama, S; Oinats, A; Connors, M; Baishev, D

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 129 ( 7 ) 2024.7

On the Factors Controlling the Relationship Between Type of Pulsating Aurora and Energy of Pulsating Auroral Electrons: Simultaneous Observations by Arase Satellite, Ground-Based All-Sky Imagers and EISCAT Radar Open Access

Ito, Y; Hosokawa, K; Ogawa, Y; Miyoshi, Y; Tsuchiya, F; Fukizawa, M; Kasaba, Y; Kazama, Y; Oyama, S; Murase, K; Nakamura, S; Kasahara, Y; Matsuda, S; Kasahara, S; Hori, T; Yokota, S; Keika, K; Matsuoka, A; Teramoto, M; Shinohara, I

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 129 ( 7 ) 2024.7

Occurrence of Mesospheric Frontal Structures Over the High Latitude Station, Tromsø, Norway Open Access

Chauhan, N; Shiokawa, K; Gurubaran, S; Nozawa, S; Oyama, SI; Nakamura, T

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 129 ( 7 ) 2024.7

Westward Excursion of Pc1/EMIC Waves and Their Source Protons: Paradoxical Observations From Ground and Space Open Access

Yin, ZF; Zhou, XZ; Hu, ZJ; Yue, C; Zong, QG; Liu, ZY; Liu, JJ; Shiokawa, K; Oyama, SI; Baishev, D

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 129 ( 5 ) 2024.5

Statistical Analysis of Low-Latitude Boundary of Polar-Type Medium-Scale Traveling Ionospheric Disturbances Observed by a 630-nm Airglow Imager at Nyrölä, Finland Open Access

Sato, M; Shiokawa, K; Oyama, S; Otsuka, Y; Shinbori, A; Oksanen, A

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 129 ( 4 ) 2024.4

Thermospheric Wind Response to March 2023 Storm: Largest Wind Ever Observed With a Fabry-Perot Interferometer in Tromsø, Norway Since 2009 Open Access

Oyama, S; Vanhamäki, H; Cai, L; Shinbori, A; Hosokawa, K; Sakanoi, T; Shiokawa, K; Aikio, A; Virtanen, II; Ogawa, Y; Miyoshi, Y; Kurita, S; Nishitani, N

SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS Vol. 22 ( 3 ) 2024.2

Longitudinal Development of Cosmic Noise Absorption Based on Multipoint Observations at Subauroral Latitudes During Storm-Time Substorms on 25-28 August 2018 Open Access

Kato, Y; Shiokawa, K; Tanaka, Y; Ozaki, M; Kadokura, A; Oyama, SI; Oinats, A; Connors, M; Baishev, D

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 129 ( 1 ) 2024.1

Correspondence of Pi2 Pulsations, Aurora Luminosity, and Plasma Flux Fluctuation Near a Substorm Brightening Aurora: Arase Observations

Chen, L; Shiokawa, K; Miyoshi, Y; Oyama, S; Jun, CW; Ogawa, Y; Hosokawa, K; Kazama, Y; Wang, SY; Tam, SWY; Chang, TF; Wang, BJ; Asamura, K; Kasahara, S; Yokota, S; Hori, T; Keika, K; Kasaba, Y; Kumamoto, A; Tsuchiya, F; Shoji, M; Kasahara, Y; Matsuoka, A; Shinohara, I; Nakamura, S

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 128 ( 10 ) 2023.10

An Implication of Detecting the Internal Modulation in a Pulsating Aurora: A Conjugate Observation by the Arase Satellite and All-Sky Imagers

Nanjo S., Ebukuro S., Nakamura S., Miyoshi Y., Kurita S., Oyama S. -I., Ogawa Y., Keika K., Kasahara Y., Kasahara S., Matsuoka A., Hori T., Yokota S., Matsuda S., Shinohara I., Wang S. -Y., Kazama Y., Jun C. -W., Kitahara M., Hosokawa K.

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 128 ( 8 ) 2023.8

A Ground-Based Instrument Suite for Integrated High-Time Resolution Measurements of Pulsating Aurora With Arase

Hosokawa K., Oyama S. -I., Ogawa Y., Miyoshi Y., Kurita S., Teramoto M., Nozawa S., Kawabata T., Kawamura Y., Tanaka Y. -M., Miyaoka H., Kataoka R., Shiokawa K., Brandstrom U., Turunen E., Raita T., Johnsen M. G., Hall C., Hampton D., Ebihara Y., Kasahara Y., Matsuda S., Shinohara I., Fujii R.

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 128 ( 8 ) 2023.8

IMF Dependence of Midnight Bifurcation in the Thermospheric Wind at an Auroral Latitude Based on Nine Winter Measurements in Tromso, Norway Open Access

Oyama S., Hosokawa K., Vanhamaki H., Aikio A., Sakanoi T., Cai L., Virtanen I. I., Shiokawa K., Nishitani N., Shinbori A., Ogawa Y.

GEOPHYSICAL RESEARCH LETTERS Vol. 50 ( 14 ) 2023.7

Geomagnetic activity dependence and dawn-dusk asymmetry of thermospheric winds from 9-year measurements with a Fabry-Perot interferometer in Tromso, Norway Open Access

Oyama Shin-ichiro, Aikio Anita, Sakanoi Takeshi, Hosokawa Keisuke, Vanhamaki Heikki, Cai Lei, Virtanen Ilkka, Pedersen Marcus, Shiokawa Kazuo, Shinbori Atsuki, Nishitani Nozomu, Ogawa Yasunobu

EARTH PLANETS AND SPACE Vol. 75 ( 1 ) 2023.5

Ionospheric modulation by EMIC wave-driven proton precipitation: Observations and simulations Invited Reviewed International coauthorship Open Access

(101) Tian, X., Y. Yu, F. Gong, L. Ma, J. Cao, S. C. Solomon, P. R. Shreedevi, K. Shiokawa, Y. Otsuka, S. Oyama, Y. Miyoshi

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 2023.1

Multi-event analysis of magnetosphere-ionosphere coupling of nighttime medium-scale traveling ionospheric disturbances from the ground and the Arase satellite Invited Reviewed Open Access

(100) Kawai, K., K. Shiokawa, Y. Otsuka, S. Oyama, M. G. Connors, Y. Kasahara, Y. Kasaba, S. Nakamura, F. Tsuchiya, A. Kumamoto, A. Shinbori, A. Matsuoka, I. Shinohara, and Y. Miyoshi

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 2023.1

A statistical study of longitudinal extent of Pc1 pulsations using seven PWING ground stations at subauroral latitudes Invited Reviewed Open Access

(99) Liu, J., K. Shiokawa, S. Oyama, Y. Otsuka, C. W. Jun, M. Nose, T. Nagatsuma, K. Sakaguchi, A. Kadokura, M. Ozaki, M. Connors, D. Baishev, N. Nishitani, A. Oinats, V. Kurkin and T. Raita

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 2023.1

Plasma-neutral gas interactions in various space environments: Assessment beyond simplified approximations as a Voyage 2050 theme Open Access

Yamauchi Masatoshi, De Keyser Johan, Parks George, Oyama Shin-ichiro, Wurz Peter, Abe Takumi, Beth Arnaud, Daglis Ioannis A., Dandouras Iannis, Dunlop Malcolm, Henri Pierre, Ivchenko Nickolay, Kallio Esa, Kucharek Harald, Liu Yong C-M, Mann Ingrid, Marghitu Octav, Nicolaou Georgios, Rong Zhaojin, Sakanoi Takeshi, Saur Joachim, Shimoyama Manabu, Taguchi Satoshi, Tian Feng, Tsuda Takuo, Tsurutani Bruce, Turner Drew, Ulich Thomas, Yau Andrew, Yoshikawa Ichiro

EXPERIMENTAL ASTRONOMY Vol. 54 ( 2-3 ) page： 521 - 559 2022.12

Thermospheric wind response to a sudden ionospheric variation in the trough: event at a pseudo-breakup during geomagnetically quiet conditions Reviewed International coauthorship Open Access

Oyama, Si., Vanhamäki, H., Cai, L. et al.

Earth, Planets and Space Vol. 74 ( 154 ) 2022.10

Observation of Source Plasma and Field Variations of a Substorm Brightening Aurora at L similar to 6 by a Ground-Based Camera and the Arase Satellite on 12 October 2017

Chen L., Shiokawa K., Miyoshi Y., Oyama S., Jun C-W, Ogawa Y., Hosokawa K., Inaba Y., Kazama Y., Wang S. Y., Tam S. W. Y., Chang T. F., Wang B. J., Asamura K., Kasahara S., Yokota S., Hori T., Keika K., Kasaba Y., Kumamoto A., Tsuchiya F., Shoji M., Kasahara Y., Matsuoka A., Shinohara I, Imajo S., Nakamura S., Kitahara M.

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 127 ( 11 ) 2022.10

Slow Contraction of Flash Aurora Induced by an Isolated Chorus Element Ranging From Lower-Band to Upper-Band Frequencies in the Source Region Open Access

Ozaki Mitsunori, Yagitani Satoshi, Shiokawa Kazuo, Tanaka Yoshimasa, Ogawa Yasunobu, Hosokawa Keisuke, Kasahara Yoshiya, Ebihara Yusuke, Miyoshi Yoshizumi, Imamura Kousuke, Kataoka Ryuho, Oyama Shin-ichiro, Chida Teppei, Kadokura Akira

GEOPHYSICAL RESEARCH LETTERS Vol. 49 ( 9 ) 2022.5

Altitude of pulsating arcs as inferred from tomographic measurements Open Access

Safargaleev Vladimir, Sergienko Tima, Hosokawa Keisuke, Oyama Shin-ichiro, Ogawa Yasunobu, Miyoshi Yoshizumi, Kurita Satoshi, Fujii Ryochi

EARTH PLANETS AND SPACE Vol. 74 ( 1 ) 2022.2

Study of an Equatorward Detachment of Auroral Arc From the Oval Using Ground-Space Observations and the BATS-R-US-CIMI Model Open Access

Yadav Sneha, Shiokawa K., Oyama S., Inaba Y., Takahashi N., Seki K., Keika K., Chang Tzu-Fang, Tam S. W. Y., Wang B. J., Kazama Y., Wang S. Y., Asamura K., Kasahara S., Yokota S., Hori T., Kasaba Y., Tsuchiya F., Kumamoto A., Shoji M., Kasahara Y., Matsuoka A., Matsuda S., Jun C. W., Imajo S., Miyoshi Y., Shinohara I

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 126 ( 12 ) 2021.12

Multipoint Measurement of Fine-Structured EMIC Waves by Arase, Van Allen Probe A, and Ground Stations Open Access

Matsuda S., Miyoshi Y., Kasahara Y., Blum L., Colpitts C., Asamura K., Kasaba Y., Matsuoka A., Tsuchiya F., Kumamoto A., Teramoto M., Nakamura S., Kitahara M., Shinohara I, Reeves G., Spence H., Shiokawa K., Nagatsuma T., Oyama S., Mann I. R.

GEOPHYSICAL RESEARCH LETTERS Vol. 48 ( 23 ) 2021.11

Simulated seasonal impact on middle atmospheric ozone from high-energy electron precipitation related to pulsating aurorae Open Access

Verronen Pekka T., Kero Antti, Partamies Noora, Szelag Monika E., Oyama Shin-Ichiro, Miyoshi Yoshizumi, Turunen Esa

ANNALES GEOPHYSICAE Vol. 39 ( 5 ) page： 883 - 897 2021.10

Periodicities and Colors of Pulsating Auroras: DSLR Camera Observations From the International Space Station

Nanjo Sota, Hozumi Yuta, Hosokawa Keisuke, Kataoka Ryuho, Miyoshi Yoshizumi, Oyama Shin-ichiro, Ozaki Mitsunori, Shiokawa Kazuo, Kurita Satoshi

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 126 ( 10 ) 2021.10

Isolated Proton Aurora Driven by EMIC Pc1 Wave: PWING, Swarm, and NOAA POES Multi-Instrument Observations Open Access

Kim Hyangpyo, Shiokawa Kazuo, Park Jaeheung, Miyoshi Yoshizumi, Miyashita Yukinaga, Stolle Claudia, Connor Hyunju Kim, Hwang Junga, Buchert Stephan, Kwon Hyuck-Jin, Nakamura Satoko, Nakamura Kohki, Oyama Shin-Ichiro, Otsuka Yuichi, Nagatsuma Tsutomu, Sakaguchi Kaori

GEOPHYSICAL RESEARCH LETTERS Vol. 48 ( 18 ) 2021.9

Simultaneous Pulsating Aurora and Microburst Observations With Ground-Based Fast Auroral Imagers and CubeSat FIREBIRD-II Open Access

Kawamura Miki, Sakanoi Takeshi, Fukizawa Mizuki, Miyoshi Yoshizumi, Hosokawa Keisuke, Tsuchiya Fuminori, Katoh Yuto, Ogawa Yasunobu, Asamura Kazushi, Saito Shinji, Spence Harlan, Johnson Arlo, Oyama Shin'ichiro, Brandstrom Urban

GEOPHYSICAL RESEARCH LETTERS Vol. 48 ( 18 ) 2021.9

First Simultaneous Observation of a Night Time Medium-Scale Traveling Ionospheric Disturbance From the Ground and a Magnetospheric Satellite Open Access

Kawai K., Shiokawa K., Otsuka Y., Oyama S., Kasaba Y., Kasahara Y., Tsuchiya F., Kumamoto A., Nakamura S., Matsuoka A., Imajo S., Kazama Y., Wang S-Y, Tam S. W. Y., Chang T. F., Wang B. J., Asamura K., Kasahara S., Yokota S., Keika K., Hori T., Miyoshi Y., Jun C., Shoji M., Shinohara I

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 126 ( 9 ) 2021.9

Variations in Cosmic Noise Absorption in Association With Equatorward Development of the Pulsating Auroral Patch: A Case Study to Estimate the Energy Spectra of Auroral Precipitating Electrons Open Access

Miyamoto Taishiro, Oyama Shin-ichiro, Raita Tero, Hosokawa Keisuke, Miyoshi Yoshizumi, Ogawa Yasunobu, Kurita Satoshi

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 126 ( 9 ) 2021.9

Penetration of MeV electrons into the mesosphere accompanying pulsating aurorae Open Access

Miyoshi Y., Hosokawa K., Kurita S., Oyama S. -I., Ogawa Y., Saito S., Shinohara I., Kero A., Turunen E., Verronen P. T., Kasahara S., Yokota S., Mitani T., Takashima T., Higashio N., Kasahara Y., Matsuda S., Tsuchiya F., Kumamoto A., Matsuoka A., Hori T., Keika K., Shoji M., Teramoto M., Imajo S., Jun C., Nakamura S.

SCIENTIFIC REPORTS Vol. 11 ( 1 ) 2021.7

Spatial Evolution of Wave-Particle Interaction Region Deduced From Flash-Type Auroras and Chorus-Ray Tracing Open Access

Ozaki Mitsunori, Inoue Tomohiro, Tanaka Yoshimasa, Yagitani Satoshi, Kasahara Yoshiya, Shiokawa Kazuo, Miyoshi Yoshizumi, Imamura Kousuke, Hosokawa Keisuke, Oyama Shin-ichiro, Kataoka Ryuho, Ebihara Yusuke, Ogawa Yasunobu, Kadokura Akira

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 126 ( 7 ) 2021.7

Multi-event Analysis of Plasma and Field Variations in Source of Stable Auroral Red (SAR) Arcs in Inner Magnetosphere during Non-storm-time Substorms Reviewed International coauthorship Open Access

Inaba, Y., K. Shiokawa1, S. Oyama et al.

Journal of Geophysical Research: Space Physics Vol. 126 ( 4 ) 2021.4

Over-darkening of pulsating aurora Reviewed International journal Open Access

Hosokawa, K., Y. Miyoshi, S.-I. Oyama, Y. Ogawa, S. Kurita, Y. Kasahara, Y. Kasaba, S. Yagitani, S. Matsuda, M. Ozaki, F. Tsuchiya, A. Kumamoto, T. Takashima, I. Shinohara, and R. Fujii

Journal of Geophysical Research: Space Physics Vol. 126 ( 4 ) 2021.4

Formation of an additional density peak in the bottom side of the sodium layer associated with the passage of multiple mesospheric frontal systems Reviewed International coauthorship Open Access

Narayanan Viswanathan Lakshmi, Nozawa Satonori, Oyama Shin-Ichiro, Mann Ingrid, Shiokawa Kazuo, Otsuka Yuichi, Saito Norihito, Wada Satoshi, Kawahara Takuya D., Takahashi Toru

ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. 21 ( 4 ) page： 2343 - 2361 2021.2

Study of Spatiotemporal Development of Global Distribution of Magnetospheric ELF/VLF Waves Using Ground-Based and Satellite Observations, and RAM-SCB Simulations, for the March and November 2017 Storms Open Access

Takeshita Yuhei, Shiokawa Kazuo, Miyoshi Yoshizumi, Ozaki Mitsunori, Kasahara Yoshiya, Oyama Shin-ichiro, Connors Martin, Manninen Jyrki, Jordanova Vania K., Baishev Dmitry, Oinats Alexey, Kurkin Vladimir

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 126 ( 2 ) 2021.2

OI 630.0-nm and N-2 1PG Emissions in Pulsating Aurora Events Observed by an Optical Spectrograph at Tromso, Norway Reviewed International coauthorship

Tsuda T. T., Li C., Hamada S., Hosokawa K., Oyama S. -I., Nozawa S., Kawabata T., Mizuno A., Kurihara J., Nishiyama T., Kosch M. J.

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 125 ( 12 ) 2020.12

Relativistic Electron Microbursts as High-Energy Tail of Pulsating Aurora Electrons Reviewed Open Access

Miyoshi Y., Saito S., Kurita S., Asamura K., Hosokawa K., Sakanoi T., Mitani T., Ogawa Y., Oyama S., Tsuchiya F., Jones S. L., Jaynes A. N., Blake J. B.

GEOPHYSICAL RESEARCH LETTERS Vol. 47 ( 21 ) 2020.11

An Ephemeral Red Arc Appeared at 68 degrees MLat at a Pseudo Breakup During Geomagnetically Quiet Conditions Reviewed International coauthorship Open Access

Oyama S., Shinbori A., Ogawa Y., Kellinsalmi M., Raita T., Aikio A., Vanhamaeki H., Shiokawa K., Virtanen I., Cai L., Workayehu A. B., Pedersen M., Kauristie K., Tsuda T. T., Kozelov B., Demekhov A., Yahnin A., Tsuchiya F., Kumamoto A., Kasahara Y., Matsuoka A., Shoji M., Teramoto M., Lester M.

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 125 ( 10 ) 2020.10

Plasma and Field Observations in the Magnetospheric Source Region of a Stable Auroral Red (SAR) Arc by the Arase Satellite on 28 March 2017 Reviewed Open Access

Inaba Yudai, Shiokawa Kazuo, Oyama Shin-ichiro, Otsuka Yuichi, Oksanen Arto, Shinbori Atsuki, Gololobov Artem Yu, Miyoshi Yoshizumi, Kazama Yoichi, Wang Shiang-Yu, Tam Sunny W. Y., Chang Tzu-Fang, Wang Bo-Jhou, Yokota Shoichiro, Kasahara Satoshi, Keika Kunihiro, Hori Tomoaki, Matsuoka Ayako, Kasahara Yoshiya, Kumamoto Atsushi, Kasaba Yasumasa, Tsuchiya Fuminori, Shoji Masafumi, Shinohara Iku, Stolle Claudia

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 125 ( 10 ) 2020.10

Estimation of the emission altitude of pulsating aurora using the five-wavelength photometer Reviewed Open Access

Kawamura Yuki, Hosokawa Keisuke, Nozawa Satonori, Ogawa Yasunobu, Kawabata Tetsuya, Oyama Shin-Ichiro, Miyoshi Yoshizumi, Kurita Satoshi, Fujii Ryoichi

EARTH PLANETS AND SPACE Vol. 72 ( 1 ) 2020.7

Development of low-cost multi-wavelength imager system for studies of aurora and airglow Reviewed Open Access

Ogawa Y., Tanaka Y., Kadokura A., Hosokawa K., Ebihara Y., Motoba T., Gustaysson B., Brandstrom U., Sato Y., Oyama S., Ozaki M., Raita T., Sigernes F., Nozawa S., Shiokawa K., Kosch M., Kauristie K., Hall C., Suzuki S., Miyoshi Y., Gerrard A., Miyaoka H., Fujii R.

POLAR SCIENCE Vol. 23 2020.3

Multievent Analysis of Oscillatory Motion of Medium-Scale Traveling Ionospheric Disturbances Observed by a 630-nm Airglow Imager Over Tromso Reviewed Open Access

Yadav Sneha, Shiokawa K., Oyama S., Otsuka Y.

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 125 ( 3 ) 2020.3

Fine-Scale Visualization of Aurora in a Wide Area Using Color Digital Camera Images From the International Space Station Reviewed Open Access

Nanjo Sota, Hozumi Yuta, Hosokawa Keisuke, Kataoka Ryuho, Miyoshi Yoshizumi, Oyama Shin-ichiro, Ozaki Mitsunori, Shiokawa Kazuo, Kurita Satoshi

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 125 ( 3 ) 2020.3

Multiple time-scale beats in aurora: precise orchestration via magnetospheric chorus waves Reviewed Open Access

Hosokawa K., Miyoshi Y., Ozaki M., Oyama S- I, Ogawa Y., Kurita S., Kasahara Y., Kasaba Y., Yagitani S., Matsuda S., Tsuchiya F., Kumamoto A., Kataoka R., Shiokawa K., Raita T., Turunen E., Takashima T., Shinohara I, Fujii R.

SCIENTIFIC REPORTS Vol. 10 ( 1 ) 2020.2

Potential for the measurement of mesosphere and lower thermosphere (MLT) wind, temperature, density and geomagnetic field with Superconducting Submillimeter-Wave Limb-Emission Sounder 2 (SMILES-2) Reviewed Open Access

Baron Philippe, Ochiai Satoshi, Dupuy Eric, Larsson Richard, Liu Huixin, Manago Naohiro, Murtagh Donal, Oyama Shin-ichiro, Sagawa Hideo, Saito Akinori, Sakazaki Takatoshi, Shiotani Masato, Suzuki Makoto

ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. 13 ( 1 ) page： 219 - 237 2020.1

Diffuse and Pulsating Aurora Reviewed

Nishimura Yukitoshi, Lessard Marc R., Katoh Yuto, Miyoshi Yoshizumi, Grono Eric, Partamies Noora, Sivadas Nithin, Hosokawa Keisuke, Fukizawa Mizuki, Samara Marilia, Michell Robert G., Kataoka Ryuho, Sakanoi Takeshi, Whiter Daniel K., Oyama Shin-ichiro, Ogawa Yasunobu, Kurita Satoshi

SPACE SCIENCE REVIEWS Vol. 216 ( 1 ) 2020.1

Longitudinal Extent of Magnetospheric ELF/VLFWaves using Multipoint PWING Ground Stations at Subauroral Latitudes Reviewed Open Access

Takeshita Yuhei, Shiokawa Kazuo, Ozaki Mitsunori, Manninen Jyrki, Oyama Shin-Ichiro, Connors Martin, Baishev Dmitry, Kurkin Vladimir, Oinats Alexey

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 124 ( 12 ) page： 9881 - 9892 2019.12

Ground Echoes Observed by the Meteor Radar and High-Speed Auroral Observations in the Substorm Growth Phase Reviewed

Kozlovsky A., Shalimov S., Oyama S., Hosokawa K., Lester M., Ogawa Y., Hall C.

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 2019.11

High-latitude thermospheric wind study using a Fabry-Perot interferometer at Tromso in Norway: averages and variations during quiet times Reviewed

Xu Heqiucen, Shiokawa Kazuo, Oyama Shin-ichiro, Nozawa Satonori

EARTH PLANETS AND SPACE Vol. 124 ( 11 ) page： 9278 - 9292 2019.11

Thermospheric wind variations observed by a Fabry-Perot interferometer at Tromso, Norway, at substorm onsets Reviewed Open Access

Xu Heqiucen, Shiokawa Kazuo, Oyama Shin-ichiro, Otsuka Yuichi

EARTH PLANETS AND SPACE Vol. 71 ( 1 ) 2019.10

Fabry-Perot Interferometer Observations of Thermospheric Horizontal Winds During Magnetospheric Substorms Reviewed Open Access

Cai L., Oyama S., Aikio A., Vanhamaki H., Virtanen I

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 71 ( 1 ) 2019.8

Tracking the Region of High Correlation Between Pulsating Aurora and Chorus: Simultaneous Observations With Arase Satellite and Ground-Based All-Sky Imager in Russia Reviewed Open Access

Kawamura S., Hosokawa K., Kurita S., Oyama S., Miyoshi Y., Kasahara Y., Ozaki M., Matsuda S., Matsuoka A., Kozelov B., Kawamura Y., Shinohara I

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 2019.8

Visualization of rapid electron precipitation via chorus element wave-particle interactions Reviewed Open Access

Ozaki Mitsunori, Miyoshi Yoshizumi, Shiokawa Kazuo, Hosokawa Keisuke, Oyama Shin-ichiro, Kataoka Ryuho, Ebihara Yusuke, Ogawa Yasunobu, Kasahara Yoshiya, Yagitani Satoshi, Kasaba Yasumasa, Kumamoto Atsushi, Tsuchiya Fuminori, Matsuda Shoya, Katoh Yuto, Hikishima Mitsuru, Kurita Satoshi, Otsuka Yuichi, Moore Robert C., Tanaka Yoshimasa, Nose Masahito, Nagatsuma Tsutomu, Nishitani Nozomu, Kadokura Akira, Connors Martin, Inoue Takumi, Matsuoka Ayako, Shinohara Iku

NATURE COMMUNICATIONS Vol. 124 ( 5 ) 2019.5

A PROPOSAL FOR SATELLITE OBSERVATION OF THE WHOLE ATMOSPHERE - SUPERCONDUCTING SUBMILLIMETER-WAVE LIMB-EMISSION SOUNDER (SMILES-2) Reviewed Open Access

Shiotani M., Saito A., Sakazaki T., Ochiai S., Baron P., Nishibori T., Suzuki M., Abe T., Maezawa H., Oyama S.

2019 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS 2019) Vol. 124 ( 5 ) page： 3709 - 3728 2019.5

Spatiotemporal development of pulsating auroral patch associated with discrete chorus elements: Arase and PWING observations Reviewed Open Access

Ozaki M., Shiokawa K., Miyoshi Y., Hosokawa K., Oyama S., Yagitani S., Kasahara Y., Kasaba Y., Matsuda S., Kataoka R., Ebihara Y., Ogawa Y., Otsuka Y., Kurita S., Moore R. C., Tanaka Y. -M., Nose M., Nagatsuma T., Connors M., Nishitani N., Hikishima M., Kumamoto A., Tsuchiya F., Kadokura A., Nishiyama T., Inoue T., Imamura K., Matsuoka A., Shinohara I.

2019 URSI ASIA-PACIFIC RADIO SCIENCE CONFERENCE (AP-RASC) Vol. 124 ( 4 ) page： 2769 - 2778 2019.4

Rapid Loss of Relativistic Electrons by EMIC Waves in the Outer Radiation Belt Observed by Arase, Van Allen Probes, and the PWING Ground Stations Reviewed Open Access

Kurita S., Miyoshi Y., Shiokawa K., Higashio N., Mitani T., Takashima T., Matsuoka A., Shinohara I., Kletzing C. A., Blake J. B., Claudepierre S. G., Connors M., Oyama S., Nagatsuma T., Sakaguchi K., Baishev D., Otsuka Y.

GEOPHYSICAL RESEARCH LETTERS Vol. 10 ( 257 ) 2019.1

Electrostatic Electron Cyclotron Harmonic Waves as a Candidate to Cause Pulsating Auroras Reviewed Open Access

Fukizawa M., Sakanoi T., Miyoshi Y., Hosokawa K., Shiokawa K., Katoh Y., Kazama Y., Kumamoto A., Tsuchiya F., Miyashita Y., Tanaka Y-M., Kasahara Y., Ozaki M., Matsuoka A., Matsuda S., Hikishima M., Oyama S., Ogawa Y., Kurita S., Fujii R.

GEOPHYSICAL RESEARCH LETTERS page： 8788 - 8791 2019

Microscopic Observations of Pulsating Aurora Associated With Chorus Element Structures: Coordinated Arase Satellite-PWING Observations Reviewed

Ozaki M., Shiokawa K., Miyoshi Y., Hosokawa K., Oyama S., Yagitani S., Kasahara Y., Kasaba Y., Matsuda S., Kataoka R., Ebihara Y., Ogawa Y., Otsuka Y., Kurita S., Moore R. C., Tanaka Y. -M., Nose M., Nagatsuma T., Connors M., Nishitani N., Katoh Y., Hikishima M., Kumamoto A., Tsuchiya F., Kadokura A., Nishiyama T., Inoue T., Imamura K., Matsuoka A., Shinohara I.

GEOPHYSICAL RESEARCH LETTERS 2019

Height-dependent ionospheric variations in the vicinity of nightside poleward expanding aurora after substorm onset Reviewed Open Access

Oyama, S., Y. Miyoshi, K. Shiokawa, J. Kurihara, T. T. Tsuda, and B. J. Watkins

J. Geophys. Res. Space Physics Vol. 45 ( 23 ) page： 12720 - 12729 2018.12

Generation of atmospheric gravity waves in the polar thermosphere in response to auroral activity Reviewed

Oyama, S., and B. J. Watkins

Space Science Review Vol. 45 ( 23 ) page： 12661 - 12668 2018.12

Variance of the vertical ion speed measured with the EISCAT UHF radar in the polar lower ionosphere at Tromsoe, Norway Reviewed Open Access

Oyama, S., A. Brekke, T. T. Tsuda, J. Kurihara, and B. J. Watkins

J. Geophys. Res. Vol. 45 ( 22 ) page： 12125 - 12134 2018.11

Purple Auroral Rays and Global Pc1 Pulsations Observed at the CIR-Associated Solar Wind Density Enhancement on 21 March 2017 Reviewed Open Access

Shiokawa K., Ozaki M., Kadokura A., Endo Y., Sakanoi T., Kurita S., Miyoshi Y., Oyama S. -I., Connors M., Schofield I., Ruohoniemi J. M., Nose M., Nagatsuma T., Sakaguchi K., Baishev D. G., Pashinin A., Rakhmatulin R., Shevtsov B., Poddelsky I., Engebretson M., Raita Tero, Tanaka Y. -M., Shinohara M., Teramoto M., Nomura R., Fujimoto A., Matsuoka A., Higashio N., Takashima T., Shinohara I., Albert Jay M.

GEOPHYSICAL RESEARCH LETTERS Vol. 45 ( 20 ) page： 10819-10828 2018.10

Auroral molecular-emission effects on the atomic oxygen line at 777.4nm Reviewed Open Access

Oyama Shin-ichiro, Tsuda Takuo T., Hosokawa Keisuke, Ogawa Yasunobu, Miyoshi Yoshizumi, Kurita Satoshi, Kero Antti E., Fujii Ryoichi, Tanaka Yoshimasa, Mizuno Akira, Kawabata Tetsuya, Gustavsson Bjorn, Leyser Thomas

EARTH PLANETS AND SPACE Vol. 70 2018.10

Survey of conditions for artificial aurora experiments by the second electron gyro-harmonic at EISCAT Tromso using dynasonde data Reviewed Open Access

Tsuda T. T., Rietveld M. T., Kosch M. J., Oyama S., Ogawa Y., Hosokawa K., Nozawa S., Kawabata T., Mizuno A.

EARTH PLANETS AND SPACE Vol. 70 2018.6

Survey of conditions for artificial aurora experiments at EISCAT Tromso using dynasonde data Reviewed Open Access

Tsuda T. T., Rietveld M. T., Kosch M. J., Oyama S., Hosokawa K., Nozawa S., Kawabata T., Mizuno A., Ogawa Y.

EARTH PLANETS AND SPACE Vol. 70 2018.3

Ground-based instruments of the PWING project to investigate dynamics of the inner magnetosphere at subauroral latitudes as a part of the ERG-ground coordinated observation network Reviewed Open Access

Shiokawa Kazuo, Katoh Yasuo, Hamaguchi Yoshiyuki, Yamamoto Yuka, Adachi Takumi, Ozaki Mitsunori, Oyama Shin-Ichiro, Nose Masahito, Nagatsuma Tsutomu, Tanaka Yoshimasa, Otsuka Yuichi, Miyoshi Yoshizumi, Kataoka Ryuho, Takagi Yuki, Takeshita Yuhei, Shinbori Atsuki, Kurita Satoshi, Hori Tomoaki, Nishitani Nozomu, Shinohara Iku, Tsuchiya Fuminori, Obana Yuki, Suzuki Shin, Takahashi Naoko, Seki Kanako, Kadokura Akira, Hosokawa Keisuke, Ogawa Yasunobu, Connors Martin, Ruohoniemi J. Michael, Engebretson Mark, Turunen Esa, Ulich Thomas, Manninen Jyrki, Raita Tero, Kero Antti, Oksanen Arto, Back Marko, Kauristie Kirsti, Mattanen Jyrki, Baishev Dmitry, Kurkin Vladimir, Oinats Alexey, Pashinin Alexander, Vasilyev Roman, Rakhmatulin Ravil, Bristow William, Karjala Marty

EARTH PLANETS AND SPACE Vol. 69 2017.11

Simultaneous FPI and TMA Measurements of the Lower Thermospheric Wind in the Vicinity of the Poleward Expanding Aurora After Substorm Onset Reviewed Open Access

Oyama Shin-ichiro, Kubota Ken, Morinaga Takatoshi, Tsuda Takuo T., Kurihara Junichi, Larsen Miguel F., Yamamoto Masayuki, Cai Lei

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 122 ( 10 ) page： 10864-10875 2017.10

Energetic electron precipitation and auroral morphology at the substorm recovery phase Reviewed Open Access

Oyama S., Kero A., Rodger C. J., Clilverd M. A., Miyoshi Y., Partamies N., Turunen E., Raita T., Verronen P. T., Saito S.

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 122 ( 6 ) page： 6508-6527 2017.5

Measurement of thermospheric temperatures using OMTI Fabry-Perot interferometers with 70-mm etalon Reviewed Open Access

Nakamura Y., Shiokawa K., Otsuka Y., Oyama S., Nozawa S., Komolmis T., Komonjida S., Neudegg Dave, Yuile Colin, Meriwether J., Shinagawa H., Jin H.

EARTH PLANETS AND SPACE Vol. 69 2017.4

Mesospheric ozone destruction by high-energy electron precipitation associated with pulsating aurora Reviewed

Turunen, E., A. Kero, P. T. Verronen, Y. Miyoshi, S.-I. Oyama, and S. Saito

J. Geophys. Res. Atmos. 2016.9

Thermospheric Nocturnal Wind Climatology Observed by Fabry-Perot Interferometers over the Asia-Oceania Region Reviewed Open Access

Yatagai, A., and S. Oyama

J. Meteorol. Soc. Japan 2016.8

Lower thermospheric wind variations in auroral patches during the substorm recovery phase Reviewed Open Access

Shin-ichiro Oyama, Kazuo Shiokawa, Yoshizumi Miyoshi, Keisuke Hosokawa, Brenton J. Watkins, Junichi Kurihara, Takuo T. Tsuda andChristopher T. Fallen

J. Geophys. Res., Space Physics Vol. 121 ( 4 ) page： 3564-3577 2016.5

Relation between fine structure of energy spectra for pulsating aurora electrons and frequency spectra of whistler mode chorus waves Reviewed Open Access

Miyoshi, Y., S. Saito, K. Seki, T. Nishiyama, R. Kataoka, K. Asamura, Y. Katoh, Y. Ebihara, T. Sakanoi, M. Hirahara, S. Oyama, S. Kurita, and O. Santolik

J. Geophys. Res. Space Physics 2015.8

A case study on generation mechanisms of a sporadic sodium layer above Tromsoe (69.6N) during a night of high auroral activity Reviewed Open Access

Takahashi, T., Nozawa, S., Tsuda, T. T., Ogawa, Y., Saito, N., Hidemori, T., Kawahara, T. D., Hall, C., Fujiwara, H., Matuura, N., Brekke, A., Tsutsumi, M., Wada, S., Kawabata, T., Oyama, S., and Fujii, R

Ann. Geophys. 2015.8

Statistical study of auroral fragmentation into patches Reviewed Open Access

Hashimoto, A., K. Shiokawa, Y. Otsuka, S.-i. Oyama, S. Nozawa, T. Hori, M. Lester, and M. G. Johnsen

J. Geophys. Res. Space Physics 2015.7

Energetic electron precipitation associated with pulsating aurora: EISCAT and Van Allen Probe observations Reviewed Open Access

Miyoshi, Y., S. Oyama, S. Saito, S. Kurita, H. Fujiwara, R. Kataoka, Y. Ebihara, C. Kletzing, G. Reeves, O. Santolik, M. Cliverd, C. J. Rodger, E. Turunen, and F. Tsuchiya

J. Geophys. Res. Space Physics 2015.3

Approximate forms of daytime ionospheric conductance Reviewed Open Access

Ieda, A., S. Oyama, H. Vanhamäki, R. Fujii, A. Nakamizo, O. Amm, T. Hori, M. Takeda, G. Ueno, A. Yoshikawa, R. J. Redmon, W. F. Denig, Y. Kamide, and N. Nishitani

J. Geophys. Res. Space Physics 2014.11

A case study of gravity wave dissipation in the polar MLT region using sodium LIDAR and radar data Reviewed Open Access

Takahashi, T., S. Nozawa, M. Tsutsumi, C. Hall, S. Suzuki, T. T. Tsuda, T. D. Kawahara, N. Saito, S. Oyama, S. Wada, T. Kawabata, H. Fujiwara, A. Brekke, A. Manson, C. Meek, and R. Fujii

Ann. Geophys. 2014.10

Auroral fragmentation into patches Reviewed

Shiokawa, K., A. Hashimoto, T. Hori, K. Sakaguchi, Y. Ogawa, E. Donovan, E. Spanswick, M. Connors, Y. Otsuka, S. Oyama, S. Nozawa, and K. McWilliams

J. Geophys. Res. Space Physics 2014.9

Height‐dependent ionospheric variations in the vicinity of nightside poleward expanding aurora after substorm onset Reviewed Open Access

Oyama, S., Y. Miyoshi, K. Shiokawa, J. Kurihara, T. T. Tsuda, and B. J. Watkins

Vol. 119 2014.5

Decrease in sodium density observed during auroral particle precipitation over Tromsoe, Norway Reviewed Open Access

Tsuda, T., S. Nozawa, T. D. Kawahara, T. Kawabata, N. Saito, S. Wada, Y. Ogawa, S. Oyama, C. M. Hall, M. Tsutsumi, M. K. Ejiri, S. Suzuki, T. Takahashi, T. Nakamura

Geophys. Res. Let. 2013.8

Observation of nighttime medium-scale travelling ionospheric disturbances by two 630-nm airglow imagers near the auroral zone Reviewed

Shiokawa, K., M. Mori, Y. Otsuka, S. Oyama, S. Nozawa, S. Suzuki, and M. Connors

J. Atmos. Solar-Terr. Phys. 2013.4

Estimation of the layered ionospheric conductance using data from a multi-wavelength photometer at the European Incoherent Scatter (EISCAT) radar site Reviewed

Oyama, S., T. Watanabe, R. Fujii, S. Nozawa1, and T. T. Tsuda

Antarctic Record Vol. 57 ( 3 ) page： 339-356 2013

Development of low-cost sky-scanning Fabry-Perot interferometers for airglow and auroral studies Reviewed Open Access

Shiokawa, K., Y. Otsuka, S. Oyama, S. Nozawa, M. Satoh, Y. Katoh, Y. Hamaguchi, Y. Yamamoto, and J. Meriwether

Earth Planets Space 2012.11

Motion of high-latitude nighttime medium-scale traveling ionospheric disturbances associated with auroral brightening Reviewed Open Access

Shiokawa, K., M. Mori, Y. Otsuka, S. Oyama, and S. Nozawa

J. Geophys. Res. 2012.10

Mean winds, tides, and quasi-2 day waves above Bear Island Reviewed

Nozawa, S., C. M. Hall, M. Tsutsumi, A. Brekke, Y. Ogawa, T. T. Tsuda, S. Oyama, and R. Fujii

J. Atmos. Solar-Terr. Phys. 2012.5

Temporal variations of the ion-neutral collision frequency from EISCAT observations in the polar lower ionosphere during periods of geomagnetic disturbances Reviewed Open Access

Oyama, S., J. Kurihara, B. J. Watkins, T. T. Tsuda, and T. Takahashi

J. Geophys. Res. Vol. 117 ( A05308 ) 2012.3

Generation of atmospheric gravity waves in the polar thermosphere in response to auroral activity Reviewed

Oyama, S., and B. J. Watkins

Space Science Review 2011.10

Fine structure of sporadic sodium layer observed with a sodium lidar at Tromsoe, Norway Reviewed Open Access

Tsuda, T. T., S. Nozawa, T. Kawahara, T. Kawabata, N. Saito, S. Wada, C. Hall, S. Oyama, Y. Ogawa, S. Suzuki, T. Ogawa, T. Takahashi, H. Fujiwara, R. Fujii, N. Matuura, and A. Brekke

Geophys. Res. Lett. 2011.9

Variance of the vertical ion speed measured with the EISCAT UHF radar in the polar lower ionosphere at Tromsoe, Norway Reviewed Open Access

Oyama, S., A. Brekke, T. T. Tsuda, J. Kurihara, and B. J. Watkins

J. Geophys. Res. Vol. 116 ( A00K06 ) 2011.7

Lower-thermospheric wind fluctuations measured with an FPI during pulsating aurora at Tromsø, Norway Reviewed Open Access

S. Oyama, K. Shiokawa, J. Kurihara, T. T. Tsuda, S. Nozawa, Y. Ogawa, Y. Otsuka, and B. J. Watkins

Ann. Geophysicae Vol. 28 page： 1847-1857 2010.10

Language：English Publishing type：Research paper (scientific journal)

Simultaneous observations were conducted with a Fabry-Perot Interferometer (FPI) at a wavelength of 557.7 nm, an all-sky camera at a wavelength of 557.7 nm, and the European Incoherent Scatter (EISCAT) UHF radar during the Dynamics and Energetics of the Lower Thermosphere in Aurora 2 (DELTA-2) campaign in January 2009. This paper concentrated on two events during periods of pulsating aurora. The lower-thermospheric wind velocity measured with the FPI showed obvious fluctuations in both vertical and horizontal components. Of particular interest is that the location of the fluctuations was found in a darker area that appeared within the pulsating aurora. During the same time period, the EISCAT radar observed sporadic enhancements in the F-region backscatter echo power, which suggests the presence of low-energy electron (1 keV or lower) precipitation coinciding with increase in amplitude of the electromagnetic wave (at the order of 10 Hz or higher). While we have not yet identified the dominant mechanism causing the fluctuations in FPI-derived wind velocity during the pulsating aurora, the frictional heating energy dissipated by the electric-field perturbations may be responsible for the increase in ionospheric thermal energy thus modifying the local wind dynamics in the lower thermosphere.

DOI： 10.5194/angeo-28-1847-2010

Open Access

Tidal waves in the polar lower thermosphere observed using the EISCAT long run data set obtained in September 2005 Reviewed

Nozawa, S., Y. Ogawa, S. Oyama, H. Fujiwara, T. Tsuda, A. Brekke, C. M. Hall, Y. Murayama, S. Kawamura, H. Miyaoka, and R. Fujii

J. Geophy. Res. 2010.8

Links between a stratospheric sudden warming and thermal structures and dynamics in the high-latitude mesosphere, lower thermosphere, and ionosphere Reviewed Open Access

Kurihara, J., Y. Ogawa, S. Oyama, S. Nozawa , M. Tsutsumi , C. Hall , Y. Tomikawa , R. Fujii

Geophys. Res. Lett. 2010.7

Temperature enhancements and vertical winds in the lower thermosphere associated with auroral heating during the Dynamics and Energetics of the Lower Thermosphere in Aurora (DELTA) campaign Reviewed Open Access

Kurihara, J., S. Oyama, S. Nozawa, T. T. Tsuda, R. Fujii, Y. Ogawa, H. Miyaoka, N. Iwagami, T. Abe, K.-I. Oyama, M. Kosch, A. Aruliah, E. Griffin, and K. Kauristie

J. Geophys. Res. 2009.12

Ion heating in high-speed flow channel within the duskside cell of the polar-cap ion convection under large IMF-By condition Reviewed

Maeda, S., Y. Ogawa, K. Hosokawa, S. Nozawa, S. Oyama, T. Tsuda and A. Brekke

J. Geophysical Research 2009.11

Relations between proton auroras, intense electric field and ionospheric electron density depletion Reviewed Open Access

Fujii, R., Y. Iwata, S. Oyama, S. Nozawa, and Y. Ogawa

J. Geophysical Research page： 114, A09304, doi:10.1029/2009JA014319 2009.9

Spatial evolution of frictional heating and the predicted thermospheric-wind effects in the vicinity of an auroral arc measured with the Sondrestrom incoherent-scatter radar and the Reimei satellite Reviewed

Oyama, S., T. T. Tsuda, T. Sakanoi, Y. Obuchi, K. Asamura, M. Hirahara, A. Yamazaki, Y. Kasaba, R. Fujii, S. Nozawa, and B. J. Watkins

J. Geophysical Research Vol. 114 ( A07311 ) page： doi:10.1029/2009JA014091 2009.7

Acceleration mechanism of high-speed neutral wind observed in the polar lower thermosphere Reviewed Open Access

Tsuda, T. T., S. Nozawa, S. Oyama, T. Motoba, Y. Ogawa, H. Shinagawa, N. Nishitani, K. Hosokawa, N. Sato, M. Lester, and R. Fujii

J. Geophysical Research 2009.4

*Generation of the lower-thermospheric vertical wind estimated with the EISCAT KST radar at high latitudes during periods of moderate geomagnetic disturbance Reviewed Open Access

Oyama, S., B. J. Watkins, S. Maeda, H. Shinagawa, S. Nozawa, Y. Ogawa, A. Brekke, C. Lathuillere, and W. Kofman

Ann. Geophysicae Vol. 26 page： 1491-1505 2008.6

Excitation and diagnosis of cascading Langmuir waves in ionospheric plasmas at Gakona, Alaska, Reviewed

Burton, L. M., J. A. Cohen, R. Pradipta, A. Labno, M. C. Lee, O. Batishchev, D. L. Rokusek, S. P. Kuo, B. J. Watkins, and S. Oyama

Phys. Scr. 2008

Temporal evolution of pump beam self-focusing at the High-Frequency Active Auroral Research Program Reviewed Open Access

Kosch M. J., T. Pedersen, E. Mishin, M. Starks, E. Gerken-Kendall, D. Sentman, S. Oyama, B. Watkins

J. Geophysical Research 2007.8

Coordinated optical and radar observations of ionospheric pumping for a frequency pass through the second electron gyroharmonic at HAARP Reviewed Open Access

Kosch M. J., T. Pedersen, E. Mishin, S. Oyama, J. Hughes, A. Senior, B. Watkins, B. Bristow

J. Geophysical Research 2007.6

A two-dimensional simulation of thermospheric vertical winds in the vicinity of an auroral arc Reviewed Open Access

Shinagawa, H., and Oyama, S

Earth Planets and Space Vol. 58 ( 9 ) page： 58(9), 1173-1181 2006.9

Persistent enhancement of the HF pump-induced plasma line measured with a UHF diagnostic radar at HAARP Reviewed Open Access

Oyama, S., B. J. Watkins, F. T. Djuth, M. J. Kosch, P. Bernhardt, and C. J. Heinselman

J. Geophysical Research Vol. 111 ( A06309 ) page： 2005JA011363 2006.6

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Plasma lines excited by a powerful, high-frequency (HF) radio wave are studied using
data obtained with an ultrahigh frequency (UHF) radar at HAARP (High Frequency
Active Auroral Research Program) from 3 to 5 February 2005. Of particular interest is
persistent enhancement of the radar backscatter power during HF on at several HF
frequencies. The persistent enhancement is induced with the HF frequency slightly lower
than foF2 by a few hundred kHz; by contrast the persistent enhancement does not
appear when the HF frequency is equal to and higher than foF2 or lower than foF2 by
more than 500 kHz. When persistent enhancements of the radar backscatter power
appear, two case studies show that the local plasma frequency at the reflection height of
the O-mode polarization wave is close to the second or third electron gyroharmonic
frequencies, but one case study shows that the local plasma frequency at the reflection
height is significantly different from the third electron gyroharmonic frequency.

DOI： 10.1029/2005JA011363

*Application of a new beam configuration to estimate lower thermospheric vertical velocities at high latitudes with mono-static incoherent scatter radars Reviewed Open Access

Oyama, S., B. J. Watkins, S. Maeda, and J. Watermann

Radio Science Vol. 40 ( RS4005 ) page： 2004RS003205 2005.7

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

We have developed a new beam configuration for monostatic incoherent scatter (IS)
radars at high latitudes in order to estimate the vertical component of the neutral wind
velocity in the lower thermosphere (from 100 to 120 km). This method has been applied to
experiments with the Sondrestrom IS radar, Greenland, on 5 and 8 March 2004. The
measurement and the analysis methods provide various temporal and altitudinal structures
of the vertical neutral wind velocity with amplitude of a few tens of meters per second at
3 km height resolution. This paper also demonstrates how to evaluate assumptions
adopted in calculations of the vertical neutral wind velocity using experimental data on
5 and 8 March 2004. Caution should be exercised in inferring effects of variations in
the thermospheric density or the ion-neutral collision frequency in association with
vertical thermospheric motions, in particular above 112 km.

DOI： 10.1029/2004RS003205

*Vertical ion motions observed with incoherent-scatter radars in the polar lower ionosphere Reviewed

Oyama, S., B. J. Watkins, S. Nozawa, S. Maeda, and M. Conde

J. Geophysical Research Vol. 110 ( A04302 ) page： 2004JA010705 2005.4

Summer-winter dependences of day-night differences in the ion temperature in the polar upper F region Reviewed

Oyama, S., C. Lathuillere, S. Maeda, and B. J. Watkins

Geophysical Research Letter Vol. 31 ( L05806 ) page： 2003GL018820 2004.3

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

The daily variation of ion temperature observed with the
European Incoherent Scatter (EISCAT) Tromsø UHF radar in
the upper F region (from 300 to 500 km) has been found to
be significantly dependent on season. Of particular interest
is the statistics that the ion temperature at local night is
higher than that at local daytime for near solar maximum
summer conditions; by contrast no differences for winter.
Using the ion energy equation estimates of the heat
exchange with electrons suggest these local time and
seasonal differences. A case study using summer-time
data from the Sondrestrom incoherent-scatter radar
(ISR) also shows local-time dependences similar to
that observed with the Tromsø ISR. The case study
using a summer-time data from the EISCAT Svalbard
radar (ESR) shows the opposite sense. These seasonal
characteristics of the ion temperature that depend on the
observation site suggest that the day-night difference of ion
temperature in the polar upper F region has complicated
magnetic-latitudinal dependences.

DOI： 10.1029/2003GL018820

The quasi 2-day wave observed in the polar mesosphere (2): Comparison of the characteristics observed at Tromso and Poker Flat Reviewed Open Access

Nozawa, S., H. Iwahashi, A. Brekke, C. M. Hall, C. Meek, A. Manson, S. Oyama, Y. Murayama, and R. Fujii

J. Geophysical Research page： 108 , 101029/2002JD003221 2003.12

Thermospheric and ionosphric dynamics in the auroral region Reviewed

Shinagawa, H., S. Oyama, S. Nozawa, S. C. Buchert, R. Fujii, and M. Ishii

Advances in Space Research Vol. 31 ( 4 ) page： 951-956 2003.9

Field-aligned ion motions in the polar E-F transition region: Mean characteristics Reviewed Open Access

Oyama, S., S. Nozawa, S. Maeda, Y. Murayama, R. Fujii, and H. Shinagawa

J. Geophysical Research page： 108(A8), 1334, doi:10.1029/2003JA009830 2003.8

The quasi 2-day wave observed in the polar mesosphere Reviewed Open Access

Nozawa, S., S. Imaida, A. Brekke, C. Hall, C. Meek, A. Manson, S. Oyama, K. Dobashi, and R. Fujii

J. Geophysical Research page： 108, 10.1029/2002JD002440 2003.1

A comparison study of the auroral lower thermopsheric neutral winds derived by the EISCAT UHF radar and the Tromso MF radar Reviewed Open Access

Nozawa, S., A. Brekke, A. Manson, C. M. Hall, C. Meek, K. Morise, S. Oyama, K. Dobashi, and R. Fujii

J. Geophysical Research page： 107, 10.1029/2000JA007581 2002.8

Field-aligned ion motions in the E and F region Reviewed

Fujii, R., S. Oyama, S. C. Buchert, S. Nozawa, and N. Matuura

J. Geophysical Research page： 107, 10.1029/ 2001JA900148 2002.5

Effects of auroral arc on the generation of atmospheric gravity waves in the polar F-region Reviewed

Oyama, S., H. Shinagawa, S. C. Buchert, R. Fujii, S. Nozawa, M. Ishii, Y, Murayama, and W. Kofman

Advances in Space Res. Vol. 27 page： 1767-1772 2001.10

*Generation of atmospheric gravity waves associated with auroral activity in the polar F region Reviewed Open Access

Oyama, S., M. Ishii, Y. Murayama, H. Shinagawa, S. C. Buchert, S. Nozawa, R. Fujii, and W. Kofman

J. Geophysical Research Vol. 106 page： 18,543-18,554 2001.2

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Relationships between the generation of atmospheric gravity waves and
auroral activity were investigated using data on neutral
oscillations, at periods of 20-30 min,
estimated from European Incoherent Scatter radar data in the polar
F-region (150-300 km).
The equation for the neutral dispersion relation gave
the values of the wave parameters,
such as the
phase velocity and wavelength, applicable to the estimated oscillations.
These values were used to estimate the distance between the observation
position and the region where the oscillations were generated.
The estimated distance superimposed on all-sky images
taken at Kilpisjarvi suggests
that the auroral arc extended in an almost zonal direction related to
the generation of the oscillations.
The oscillations were compared with ones calculated
using the Francis model.
The phase surface of the modeled atmospheric gravity waves showed fairly
good agreement with that of the observed oscillations,
suggesting that the estimated distance is acceptable
for reproducing the estimated oscillations with the model.
It is concluded that auroral activities significantly relate to the AGW
generation in the polar thermosphere as investigated with theoretical
studies.

DOI： 10.1029/2001JA900032

Effects of atmospheric oscillations on the field-aligned ion motions in the polar F-region Reviewed Open Access

Oyama, S., S. Nozawa, S. C. Buchert, M. Ishii, S. Watari, E. Sagawa, W. Kofman, J. Lilensten, and R. Fujii

Ann. Geophysicae Vol. 18 page： 1154-1163 2000.9

Dynamics of neutral wind in the polar region observed with two Fabry-Perot interferometers Reviewed Open Access

Ishii, M., S. Oyama, S. Nozawa, R. Fujii, E. Sagawa, S. Watari, and H. Shinagawa

Earth Planets and Space Vol. 51 page： 833-844 1999.8

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