Faculty Profiles - SHIOKAWA, Kazuo

Equatorial GPS ionospheric scintillations over Kototabang, Indonesia and their relation to atmospheric waves from below Reviewed Open Access

Ogawa Tadahiko, Miyoshi Yasunobu, Otsuka Yuichi, Nakamura Takuji, Shiokawa Kazuo

EARTH PLANETS AND SPACE Vol. 61 ( 4 ) page： 397 - 410 2009

Fine structures and dynamics in auroral initial brightening at substorm onsets Reviewed Open Access

Sakaguchi K., Shiokawa K., Ieda A., Nomura R., Nakajima A., Greffen M., Donovan E., Mann I. R., Kim H., Lessard M.

ANNALES GEOPHYSICAE Vol. 27 ( 2 ) page： 623-630 2009

Propagation characteristics of nighttime mesospheric and thermospheric waves observed by optical mesosphere thermosphere imagers at middle and low latitudes Reviewed Open Access

Shiokawa K., Otsuka Y., Ogawa T.

EARTH PLANETS AND SPACE Vol. 61 ( 4 ) page： 479-491 2009

28pSP-16 Precipitation of radiation belt relativistic electrons by electromagnetic ion cyclotron waves Reviewed Open Access

Miyoshi Y., Sakaguchi K., Shiokawa K., Evans D., Albert J., Connors M., Jordanova V.

Meeting Abstracts of the Physical Society of Japan Vol. 64.1.2 ( 0 ) page： 228 2009

Characteristics of equatorial gravity waves derived from mesospheric airglow imaging observations Reviewed Open Access

Suzuki S., Shiokawa K., Liu A. Z., Otsuka Y., Ogawa T., Nakamura T.

ANNALES GEOPHYSICAE Vol. 27 ( 4 ) page： 1625 - 1629 2009

New observational deployments for SEALION-Airglow measurements using all-sky imagers Reviewed Open Access

Minoru Kubota, Mamoru Ishii, Takuya Tsugawa, Jyunpei Uemoto, Hidekatsu Jin, Yuichi Otsuka, Kazuo Shiokawa

Journal of the National Institute of Information and Communications Technology Vol. 56 ( 1-4 ) page： 299 - 307 2009

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

An airglow all-sky imager (ASI)-a new monitoring instrument-is scheduled to be set up in February 2010 at Chiang Mai, Thailand, as part of the framework of the Southeast Asia Low-latitude Ionospheric Network (SEALION) being developed in the Southeast Asian region by the National Institute of Information and Communications Technology (NICT). The ASI images airglow having an emission layer near the ionospheric F-layer in order to observe the two-dimensional structure and time evolution of such ionospheric disturbances as plasma bubbles. In Southeast Asia, the Solar-Terrestrial Environment Laboratory (STE) of Nagoya University has been conducting ASI-based observations at Kototabang, Indonesia, ever since 2002. This paper provides detailed insight into the formation, growth and propagation of plasma bubbles as derived from observational data recorded using ASI at Kototabang and using SEALION ionoson-des and GPS receivers. The functional requirements for another ASI to be installed and ASI-based observation schemes are then discussed based on that insight.

Joint observations of a traveling ionospheric disturbance with the Paratunka OMTI camera and the Hokkaido HF radar Reviewed Open Access

Koustov A., Nishitani N., Ponomarenko P. V., Shiokawa K., Suzuki S., Shevtsov B. M., MacDougall J. W.

ANNALES GEOPHYSICAE Vol. 27 ( 6 ) page： 2399 - 2406 2009

Effects of geomagnetically induced current on power grids Reviewed

Watari S, Kunitake M, Kitamura K, Hori T, Kikuchi T, Shiokawa K, Nishitani N, Kataoka R, Kamide Y, Watanabe Y

Journal of the National Institute of Information and Communications Technology Vol. 56 ( 1-4 ) page： 125 - 133 2009

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

There have been many reports that geomagnetically induced current (GIC) has affected the operation of electric power grids. Given Japan's location at lower geomagnetic latitude than its geographic latitude, the effects of GIC on electric power grids there are believed to be small, but have yet to be subjected to elaborate analysis. This paper describes the results of GIC measured in Hokkaido over a two-year period in collaboration with the National Institute of Information and Communications Technology (NICT), Hokkaido Electric Power Co., Inc., and the Solar- Terrestrial Environment Laboratory (STEL) of Nagoya University.

ULF geomagnetic anomalous changes possibly associated with 2004-2005 Sumatra earthquakes Reviewed

Other Link： http://orcid.org/0000-0001-8451-6941

S. Saroso, K. Hattori, H. Ishikawa, Y. Ida, R. Shirogane, M. Hayakawa, K. Yumoto, K. Shiokawa, M. Nishihashi

PHYSICS AND CHEMISTRY OF THE EARTH Vol. 34 ( 6-7 ) page： 343 - 349 2009

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

Anomalous ULF geomagnetic field change is considered to be one of the most convincing and promising phenomena among earthquake-related electromagnetic effects, because we expect emissions from the crust of the source region. There has been a great deal of accumulated and convincing evidence of ULF magnetic signatures before large earthquakes as reported in the previous studies. In order to verify these phenomena preceding large earthquakes and to clarify the relationship between electromagnetic phenomena and possible physical mechanism, we have investigated the data of ULF geomagnetic observations at Kototabang and Biak stations associated with the 2004/2005 Sumatra earthquakes. A case study is carried out in this work to investigate the pre-earthquake ULF geomagnetic anomalies during the Sumatra-Andaman earthquake on December 26, 2004 (magnitude Mw = 9.0 and depth = 30 km from USGS catalog), and Sumatra-Nias earthquake on March 28, 2005 (Mw = 8.7 and depth = 30 km). For the aim of finding any precursors, we have adopted the spectral density ratio analysis and transfer functions analysis based on wavelet transform method. Results of the spectral density analysis indicate similar variations to those of amplitude for the induction arrow in transfer function analysis. Both of these variations at Kototabang exhibit strange or anomalous changes from a few weeks before the Sumatra-Andaman earthquake to July 2005, while there are no apparent changes at remote station of Biak. To make these results more convincing, the fractal analysis based on a Higuchi method has been applied to the same observed data, which also show a significant change (or decrease) in mono-fractal dimension a few weeks before the earthquakes. This result would lend a further support to those by the spectral density ratio and transfer function analyses. So, we can conclude that the anomalous change as observed simultaneously by the three methods, might be a possible signature related with the earthquake preparation phase of Sumatra earthquakes. (C) 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.pce.2008.10.065

Northeastward motion of nighttime medium-scale traveling ionospheric disturbances at middle latitudes observed by an airglow imager Open Access

Longitudinal development of a substorm brightening arc Reviewed Open Access

Shiokawa K., Ieda A., Nakajima A., Sakaguchi K., Nomura R., Aslaksen T., Greffen M., Spanswick E., Donovan E., Mende S. B., McFadden J., Glassmeier K. -H., Angelopoulos V., Miyashita Y.

ANNALES GEOPHYSICAE Vol. 27 ( 5 ) page： 1935 - 1940 2009

The Upper Atmosphere and Plasma Imager/the Telescope of Visible Light (UPI/TVIS) onboard the Kaguya spacecraft Reviewed Open Access

Taguchi M., Sakanoi T., Okano S., Kagitani M., Kikuchi M., Ejiri M., Yoshikawa I., Yamazaki A., Murakami G., Yoshioka K., Kameda S., Miyake W., Nakamura M., Shiokawa K.

EARTH PLANETS AND SPACE Vol. 61 ( 12 ) page： XVII - XXIII 2009

Possible influence of ultra-fast Kelvin wave on the equatorial ionosphere evening uplifting Reviewed Open Access

Takahashi H., Abdu M. A., Wrasse C. M., Fechine J., Batista I. S., Pancheva D., Lima L. M., Batista P. P., Clemesha B. R., Shiokawa K., Gobbi D., Mlynczak M. G., Russell J. M.

EARTH PLANETS AND SPACE Vol. 61 ( 4 ) page： 455 - 462 2009

K. Shiokawa, Y. Otsuka, N. Nishitani, T. Ogawa, T. Tsugawa, T. Maruyama, S. E. Smirnov, V. V. Bychkov, B. M. Shevtso

Journal of Geophysical Research: Space Physics Vol. 113 ( A12 ) 2008.12

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

Nighttime medium-scale traveling ionospheric disturbances (MSTIDs) observed in 630-nm airglow images at middle latitudes are known to have a predominantly northwest-southeast phase surface and to move southwestward in the Northern Hemisphere of Earth. However, the mechanisms of MSTID generation and their systematic southwestward motion have not been clarified. In this paper, we report the "northeastward" motion of the MSTIDs observed at Paratunka, Far East Russia (52.97°N, 158.25°E), using an all-sky 630-nm airglow imager at 2000-2300 LT on 19 August 2007. The MSTIDs moved first southwestward but then back northeastward in the northern part of the images. The northeastward motion of the MSTIDs took place coincident with a F layer height decrease observed by an ionosonde at Paratunka. The F layer height decrease was also confirmed by an enhancement of the 630-nm airglow intensity, which seemed to propagate from northeast to southwest. This fact suggests that the F layer height decrease was caused by poleward wind enhancement rather than westward electric field. These observations imply that the F layer height decrease or the poleward thermospheric wind has some role in the northeastward turning of the MSTID propagation direction. Copyright 2008 by the American Geophysical Union.

DOI： 10.1029/2008JA013417

Precipitation of radiation belt electrons by EMIC waves, observed from ground and space Reviewed Open Access

Y. Miyoshi, K. Sakaguchi, K. Shiokawa, D. Evans, J. Albert, M. Connors, V. Jordanova

GEOPHYSICAL RESEARCH LETTERS Vol. 35 ( 23 ) 2008.12

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER GEOPHYSICAL UNION

We show evidence that left-hand polarised electromagnetic ion cyclotron (EMIC) plasma waves can cause the loss of relativistic electrons into the atmosphere. Our unique set of ground and satellite observations shows coincident precipitation of ions with energies of tens of keV and of relativistic electrons into an isolated proton aurora. The coincident precipitation was produced by wave-particle interactions with EMIC waves near the plasmapause. The estimation of pitch angle diffusion coefficients supports that the observed EMIC waves caused coincident precipitation of both ions and relativistic electrons. This study clarifies that ions with energies of tens of keV affect the evolution of relativistic electrons in the radiation belts via cyclotron resonance with EMIC waves, an effect that was first theoretically predicted in the early 1970's.

DOI： 10.1029/2008GL035727

Simultaneous THEMIS in situ and auroral observations of a small substorm Reviewed

E. Donovan, W. Liu, J. Liang, E. Spanswick, I. Voronkov, M. Connors, M. Syrjasuo, G. Baker, B. Jackel, T. Trondsen, M. Greffen, V. Angelopoulos, C. T. Russell, S. B. Mende, H. U. Frey, A. Keiling, C. W. Carlson, J. P. McFadden, K. -H. Glassmeier, U. Auster, K. Hayashi, K. Sakaguchi, K. Shiokawa, J. A. Wild, I. J. Rae

GEOPHYSICAL RESEARCH LETTERS Vol. 35 ( 17 ) 2008.8

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER GEOPHYSICAL UNION

We present ground-based and in situ observations from March 13, 2007. The THEMIS satellites were in the evening sector conjugate to THEMIS ground-based imagers. At similar to 0507 UT there was an optical onset on inner CPS field lines. This involved near-simultaneous brightening of 1 MLT hour longitudinal segment of the onset arc. The part of the arc that brightened was that closest to the equatorward boundary of the diffuse ( proton) aurora. Within one minute, a dipolarization front moved across four THEMIS satellites. Based on their locations, the order in which they detected the dipolarization front, and the auroral evolution, we assert that the expansion phase began earthward of the four satellites and evolved radially outwards. We conclude that this onset occurred in an azimuthally localized region of highly stretched field lines.

DOI： 10.1029/2008GL033794

Particle and field characteristics of broadband electrons observed by the FAST satellite during geomagnetic storms: A multievent study Reviewed Open Access

A. Nakajima, K. Shiokawa, K. Seki, J. P. McFadden, C. W. Carlson, R. J. Strangeway, K. Yumoto

Journal of Geophysical Research: Space Physics Vol. 113 ( A6 ) 2008.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Blackwell Publishing Ltd

During geomagnetic storms, remarkable electron-flux enhancements (&gt
1012 eV cm-2 s-1) over a broadband energy range (∼0.05-10 keV) are sometimes observed near the equatorward edge of the auroral oval. We call such electron flux enhancements broadband electrons (BBEs). In this paper, we identified 12 BBE events from the electron-energy spectra obtained by the Fast Auroral Snapshot (FAST) satellite during 81 large geomagnetic storms (minimum Dst index &lt
-90 nT) between September 1996 and March 2004. Ground-based magnetic field data show that the BBEs are observed ∼6-28 min after the onset of substorms during the main phase of large storms. During these events, the pitch angle distributions of electrons show isotropic features at a higher energy range above ∼1 keV, except for an upward loss cone. At a lower energy range below ∼1 keV, field-aligned downward electron fluxes are most intense, and perpendicular fluxes are weakest. These results imply that a higher-energy part of BBEs originates from higher altitudes in the inner magnetosphere and that a lower-energy part is accelerated parallel to the local magnetic field at lower altitudes near the satellite. Intense fluctuations of electric and magnetic fields and enhanced lower-frequency (0.1 Hz to 16 kHz) waves are observed during the BBEs. These characteristics are common for all BBE events. We compared lower-energy (&lt
1 keV) electron fluxes with field-aligned Poynting fluxes of the waves at 0.06-4 Hz during the BBEs. The Poynting fluxes are systematically downward with intensity comparable to that of the lower-energy electron fluxes, suggesting downward acceleration of lower-energy electrons by the observed low-frequency waves. Copyright 2008 by the American Geophysical Union.

DOI： 10.1029/2007JA013001

Correlation of substorm injections, auroral modulations, and ground Pi2 Reviewed Open Access

A. Keiling, V. Angelopoulos, D. Larson, R. Lin, J. McFadden, C. Carlson, J. W. Bonnell, F. S. Mozer, K. -H. Glassmeier, H. U. Auster, W. Magnes, S. Mende, H. Frey, A. Roux, O. LeContel, S. Frey, T. Phan, E. Donovan, C. T. Russell, I. Mann, W. Liu, X. Li, M. Fillingim, G. Parks, K. Shiokawa, J. Raeder

GEOPHYSICAL RESEARCH LETTERS Vol. 35 ( 17 ) 2008.6

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER GEOPHYSICAL UNION

In this case study we report a substorm, 23 March 2007, which exhibited oscillations with a period of similar to 135 s in three substorm phenomena all of which were one-to-one correlated. The in-situ observations are from one THEMIS spacecraft (8.3 R(E) geocentric distance) and the geosynchronous LANL-97A spacecraft. The focus here is on the intensification phase during which THEMIS was conjugate to the region of auroral brightening and its foot point was near the high-latitude ground station Kiana. The following results will be demonstrated: (1) THEMIS and LANL-97A (time-delayed) recorded periodic ion injections (> 100 keV). (2) Near-conjugate high-latitude ground magnetometer data show very large Pi2 (delta H similar to 150\ nT) with a 6-s time delay compared to the THEMIS ion injections. (3) Low-latitude ground magnetometer data also show Pi2 with the same waveform as the high-latitude Pi2 but with longer time delays (20-31 s). (4) Auroral luminosity was periodically modulated during the intensification phase. (5) All three signatures (ion injections, ground Pi2, optical modulation) had the same periodicity of similar to 135 s but with various time delays with respect to the THEMIS ion injections. These observations demonstrate that the three substorm phenomena had a common source which controlled the periodicity.

DOI： 10.1029/2008GL033969

プラズマバブルの発生位置の同定 Reviewed

木下佳紀, 中田裕之, 大塚雄一, 鷹野敏明, 島倉信, 塩川和夫, 小川忠彦

大気電気学会誌 Vol. 2 ( 1 ) page： 147 - 148 2008.5

Simultaneous appearance of isolated auroral arcs and Pc 1 geomagnetic pulsations at subauroral latitudes Reviewed Open Access

K. Sakaguchi, K. Shiokawa, Y. Miyoshi, Y. Otsuka, T. Ogawa, K. Asamura, M. Connors

Journal of Geophysical Research: Space Physics Vol. 113 ( A5 ) 2008.5

Language：English Publishing type：Research paper (scientific journal) Publisher：Blackwell Publishing Ltd

We have been conducting observations of aurora and geomagnetic pulsations at Athabasca, Canada, located at a subauroral latitude (magnetic latitude: 62°, L ∼ 4.6), using an all-sky imager and an induction magnetometer. Isolated auroral arcs at wavelengths of 557.7 nm, 630.0 nm, and 486.1 nm (H β) were often observed at latitudes separated equatorward from the main auroral oval. From a 1-year observation (4 September 2005 to 3 September 2006), we found 13 isolated arc events. All these isolated arcs occurred coincidentally with Pc 1 geomagnetic pulsations, although there were nine other Pc 1 events without isolated arcs in the field of view of the imager. The arcs were observed in both pre- and post-midnight sectors and tended to appear during the late recovery phase of geomagnetic storms. The isolated arcs had limited latitudinal and longitudinal widths of less than 230 km and 250-800 km, respectively. We found that as isolated arcs moved equatorward (poleward), the frequencies of the simultaneous Pc 1 pulsations increased (decreased). Using the Tsyganenko-02 magnetic field model, the observed Pc 1 frequencies were almost the same as the frequencies of He+ electromagnetic ion cyclotron (EMIC) waves at the equatorial plane connected to observed isolated arcs. These results indicate that interactions of spatially localized EMIC waves with ring current ions cause high-energy ion precipitation and associated isolated auroras at subauroral latitudes. These results also imply that the dynamics and instabilities in the inner magnetosphere can be monitored as low-latitude auroral emissions away from the ordinary auroral oval. Copyright 2008 by the American Geophysical Union.

DOI： 10.1029/2007JA012888