Nozaki and Kobayashi  demonstrated that a 24.5 MHz FM/CW radar with a low transmitting power of 100 W at Okinawa can sufficiently detect low-latitude F region field-aligned irregularities (FAIs). Igarashi et al.  developed a new 50 MHz scanning-beam auroral Doppler radar consisting of two sets of array antennas. This radar, located at Syowa Station, Antarctica, can observe auroral E region irregularities in a wide area.
Aurora stereoscopic observations at two distant stations was carried out in Iceland in 1993 to obtain stereo image data with longer baseline for the study of inverse algorithm and to clarify three-dimensional luminous structures of aurora [Aso et al., 1993]. Ejiri et al. [1994a] described the visible (557.7 nm) TV camera aboard the EXOS-D (Akebono) satellite that takes successive auroral images every 8 s (a snapshot image of a wide area with high spatial and temporal resolutions) and presented some preliminary results.
A 30 MHz imaging riometer was installed at Ny-Alesund (L=16) to observe spatial structure and motion of auroral absorption regions [Nishino et al., 1993]. The antenna consisting of a two-dimensional dipole array with 64 elements produces 64 pencil beams that scan an area of about 200 km square at 90 km altitude. The instrument can provide a two-dimensional image of enhanced absorption region with a spatial resolution of 20 km and temporal resolution of 1 s.
Since 1984, the National Institute of Polar Research and the Institute of Space and Astronautical Science have been studying the feasibility of a long-term circumpolar balloon experiment, called the Polar Patrol Balloon (PPB) project. After three test flights in 1987 and 1990 at Syowa Station, Antarctica, six PPB experiments were carried out in 1990 to 1993 as an Antarctic STEP project [Ejiri et al., 1993, 1994b, 1995; Nishimura et al., 1994]. Of six PPBs, PPB #1 accomplished a complete circumpolar flight over Antarctica [Ejiri et al., 1993] and measured the total force of the geomagnetic main field with an accuracy of 1 nT with a proton magnetometer [Tohyama et al., 1993]. PPB #2 was launched with scientific payloads for auroral X-rays, magnetic and electric fields. PPB #4 and #5 were equipped with payloads for measuring vector magnetic and electric fields and auroral X-rays in the auroral, polar cap and cleft/cusp regions.
Japan joined the EISCAT Scientific Association in April 1996. Matuura et al.  discussed collaboration between the Japanese scientific community and the EISCAT Scientific Association on the new Svalbard incoherent scatter radar project. They summarized some of the important research topics to pursue in conjunction with this radar: identification of the cusp region, solar wind control of the cusp, electrodynamics in the cusp and polar cap, contracted-oval substorms, and thermospheric dynamics at high latitudes.
A time-dependent three-dimensional computer simulation of equatorial F region was carried out to understand electron temperature structures observed by the Hinotori satellite near 600 km altitude in the low- and mid-latitude ionosphere [Watanabe et al., 1995; Watanabe and Oyama, 1995]. This model provides three-dimensional distributions of ion densities, electron temperature, and ion temperatures and is consistent with the equatorial electron density and temperature data from Hinotori. Su et al.  studied Hinotori observations of electron density and temperature by comparison with values from the Scheffield University plasma-ionosphere model to discuss similarities and dissimilarities between the observations and the model.
Oyama et al.  discussed energy budget in an equatorial plasma bubble to explain electron temperatures observed by Hinotori at 600 km altitude and showed from calculations that electron temperature profile inside bubble can basically be explained as a function of energy input to the bubble, ion temperature, and electron density. The calculated results are consistent with the satellite observations.
Based on in-situ observations of electron density by the Hinotori satellite, Takahashi and Oya  presented a new concept of three dimensional large scale structure of the low-latitude ionosphere. The structures are classified into two types, crest type (cusp type enhancement) and canyon type (cusp type depletion), both of which are often accompanied by plasma bubbles in their central portion. Takahashi et al.  used the same satellite data to clarify two types of equatorial plasma bubbles: one is large scale array type appearing between the sunset and local midnight, and the other type is related to local density enhancement due to substorm activity.
Much of the thermospheric research in Japan concerned the 46.5 MHz MU (Middle and Upper atmosphere) radar of the Radio Atmospheric Science Center of Kyoto University. Rishbeth and Fukao  reviewed much of this work.
Ionospheric and atmospheric disturbances due to the eruptions of Mount Pinatubo were detected by the Japanese ionospheric observation network [Igarashi et al., 1994]. Wave fronts of the disturbances traveled northward with a velocity of about 290 m/s, being comparable to a horizontal velocity of the pressure fluctuations detected by the microbarograph chain in Japan.
Low-latitude penetration of magnetospheric electric field was corroborated from low-latitude ionospheric disturbances which accompanied severe ionospheric scintillations [Tanaka, 1994]. An important feature associated with this event is the enhancement of equatorial ionization anomaly that correlates with the asymmetric ring current in the evening.
The winter D region anomalies (anomalous f-min enhancements) detected during the DYANA campaign in 1992 were analyzed to find their temporal and geographical distributions [Ohtani et al., 1993]. The f-min anomaly that might be related to planetary wave activity was most intensified around the north latitudes of 40-45 degrees, became weaker toward higher and lower latitudes, and occasionally extended down to 26 degrees.
Using data from the EISCAT CP1 observation mode, Shibata and Schlegel  studied vertical structure of atmospheric gravity waves (AGWs) associated fluctuations of ionospheric plasma parameters at altitudes of 100-240 km in daytime. They found that the essential features of AGWs can be explained in terms of the energy conservation in a dissipative thermosphere. They also derived intrinsic propagation parameters of the dominant AGW and clearly identified a downcoming AGW.
Irregularities that produce quasi-periodic scintillations of the field strength of radio waves transmitted from a satellite were investigated by numerical calculations for various shapes of plasma enhancement in the sporadic E layer, and the results were compared with observations [Maruyama, 1995].
Saito et al.  studied electric field fluctuations in the nighttime topside ionosphere at midlatitude observed by the DE-2 satellite. The fluctuations with wavelengths of several tens of kilometers and amplitudes of a few mV/m extended over several hundred kilometers along the latitude and were often detected at magnetically conjugate points in the northern and southern hemispheres.
To explain the seasonal-longitudinal variation of equatorial spread F irregularities, the Rayleigh-Taylor instability growth rates were calculated with a non-local treatment and compared with the calculations with local ionospheric parameters at the equator [Maruyama, 1994].
Ohtaka and Tanaka  presented long term variations of VHF auroral radar echo occurrences from 1978 to 1990. The diurnal variation exhibits a maximum after local midnight and a minimum around noon, and the monthly-averaged occurrences show semi-annual variations with minima in summer and winter. For the solar cycle variation, there exist two occurrence peaks: major peak in the declining phase of the sunspot number and secondary peak in the increasing phase. By analyzing data from 50 MHz auroral radar, Kunitake  showed a statistical result of the radar echoes having very narrow spectral peaks with low Doppler shifts less than 20 Hz. A mechanism responsible for this type of echoes is unknown.
Ueda et al.  studied mechanism of stimulated electromagnetic emissions, called Broad Upshifted Maximum, observed in high-frequency ionospheric heating experiments with the aid of two-dimensional electromagnetic particle computer simulation. The results show that the irregularities are important for the excitation of the emissions.
Using a two-dimensional, time-dependent model of coupled dynamics and composition, Maeda and Fujiwara  simulated dynamical response of the thermosphere to energy input associated with geomagnetic storms. The response to model storms of various durations are interpreted in terms of meridional circulation and atmospheric gravity waves.
Makita et al.  studied characteristics of extremely high latitude auroras (polar arc and polar corona), electron energies for producing these auroras, and origins of the energetic electrons. Ono  operated a high speed multi-channel photometer at Syowa Station, Antarctica to derive energy spectrum of precipitating electrons through an intensity comparison of auroral emission lines and bands. They showed that the intensity ratio of 844.6 and 427.8 nm band is a useful indicator for an average energy of precipitating electrons. This method was applied for estimation of an average energy and a total flux for active discrete auroras associated with auroral break-up [Ono and Morishima, 1994]. Using a multicolor all-sky imaging system (MAIS) and a tilting-filter photometer at Syowa Station, Takahashi et al.  investigated the dynamics of proton auroras and its relation to electron auroras that were monitored with an all-sky SIT camera. Simultaneous TV observations of pulsating auroras at three, nearly geomagnetically conjugate stations (one in Iceland and two in Antarctica) showed a distinct lack of correlation between pulsating auroras in both hemispheres for a certain period [Minatoya et al., 1995].
Motions of auroral arcs in the high-latitude morning sector (0300-0900 magnetic local time) during magnetically quiet periods was studied, which suggests that the observed duskward auroral motion is related to poleward shrinkage of the morningside oval on closed field lines [Shiokawa et al., 1995a].
Shiokawa et al.  observed low-latitude auroras in Japan with a meridian scanning photometer and all-sky TV camera. These auroras were found to occur in the region of L=2 even during moderate magnetic storms. The low-latitude aurora event on September 13, 1993 showed that this aurora occurred in association with the expansion onset of an intense magnetospheric substorm [Shiokawa et al., 1995b]. Electron auroras was theoretically studied by using the Monte Carlo method, the results of which may be applicable to low latitude electron auroras [Onda and Itikawa, 1995]. Low-latitude auroras associated with magnetic storms are very rare phenomena and therefore are not well understood.
Global features of particle precipitation and field-aligned electron acceleration during isolated substorms were investigated using energetic particle data from the DMSP F6 and F7 satellites. Some dynamical features of the precipitation region of central plasma sheet type electrons were revealed [Shiokawa and Yumoto, 1993].
A comparison study was made between the electron energy spectra calculated from electron density profiles at the 90-160 km altitudes obtained from the EISCAT radar and in-situ observations by the DMSP satellites at the top of the ionosphere [Fujii et al., 1995].
The characteristics of the large-scale electrodynamic parameters, field-aligned currents, electric fields, and electron precipitation, which are associated with auroral substorm events in the nighttime sector, was obtained through a unique analysis which places the ionospheric measurements of these parameters into the context of a generic substorm determined from global auroral images [Fujii et al., 1994; Hoffman et al., 1994].
Questions about a basic concept of the dayside field line merging are raised, and alternative new mechanisms were proposed on the IMF control of the magnetosphere and for the magnetosheath plasma injection into the magnetosphere [Matuura, 1995]. The EISCAT Svalbard radar is important to pursue mechanisms on the solar wind-magnetosphere interactions [Matuura, 1995].
Nishino et al.  reported characteristics of the low-latitude VLF hiss observed at dawn at Moshiri (L=1.6) and Kagoshima (L=1.2), Japan during a severe geomagnetic storm and discussed a generation mechanism of the band-limited hiss spectra due to hot and cold plasmas in the magnetosphere. Iwata et al.  compared storm-related energetic electrons detected by a satellite with both LF whistler-mode signals from a Decca navigation station in Japan measured at Birdsville, Australia and VLF/ELF emissions measured at Moshiri and Kagoshima. They found that the energetic electrons penetrating from the magnetosphere to low L-shell regions below L=2 generated the waves.
On the basis of application of both digital spectral analysis and field-analysis direction finding techniques, Ohta et al.  investigated subionospheric propagation characteristics of the magnetospheric whistlers observed in South China and found that very low latitude whistlers exhibit very clear additional dispersion effects near the cutoff frequencies of the subionospheric 1st- and higher-order modes. These wave properties were explained in terms of a full wave theory in the earth-ionosphere waveguide in which realistic electron density profiles of the lower ionosphere are assumed [Hayakawa et al., 1994]. Hayakawa et al.  reviewed recent activities on VLF/ELF sferics. The paper describes a new method for estimating both propagation distance and ionospheric reflection height by using a signal processing for the dispersive tails of tweek sferics near cutoff frequencies and the first attempt to apply the field-analysis direction finding to tweek sferics.
A new direction finding procedure, based on simple processing of averaged Poynting vector in time domain, for groups of nearby and distant atmospherics was developed to estimate the azimuth of a wideband ELF-VLF source, and was compared with the corresponding azimuths acquired by some other single-station techniques [Nickolaenko et al., 1994]. Baba and Hayakawa  formulated a finite element method for investigating the effect of localized perturbations in the lower ionosphere on subionospheric VLF propagation and presented a few computational results showing the effectiveness of this method.
Molchanov et al.  considered some propagation effects occurring when the ionosphere consists of several layers and found that a multi-layer structure can yield a new set of ELF resonance phenomena. The resonances appear in the space between the earth and layer interfaces or inside the layers and are liable to give rise to peaks or minima in the frequency dependencies of ELF electromagnetic fields for both cosmic and terrestrial sources.
Baba, K., and M. Hayakawa, The effect of localized ionospheric perturbations on subionospheric VLF propagation on the basis of finite element method, Radio Sci., 30, 1511-1517 (1995)
Bowman, G. G., S. Fukao, M. Yamamoto, and K. Igarashi, MU radar recorded field-aligned irregularities in the F2 region and associated sporadic-E disturbances, J. Geomag. Geoelectr., 46, 873-889 (1994)
Ejiri, M., A. Kadokura, T. Hirasawa, N. Sato, R. Fujii, H. Miyaoka, J. Nishimura, N. Yajima, T. Yamagami, S. Kokubun, H. Fukunishi, M. Yamanaka, and M. Kodama, Polar patrol balloon experiment in Antarctica, Adv. Space Res., 13, 2, 127-130 (1993)
Ejiri, M., A. Kadokura, and T. Oguti, Preliminary results of auroral dynamics observed by the ATV-VIS imager aboard EXOS-D (Akebono), J. Geomag. Geoelectr., 46, 851-860 (1994a)
Ejiri, M., J. Nishimura, N. Yajima, T. Hirasawa, R. Fujii, H. Akiyama, T. Yamagami, S. Ohta, H. Kanzawa, T. Tohyama, and S. Kokubun, Polar patrol balloon project in Japan, Adv. Space Res., 14, 2, 201-209 (1994b)
Ejiri, M., H. Akiyama, E. A. Bering, R. Fujii, M. Hayashi, Y. Hirasima, A. Kadokura, H. Kanzawa, M. Kodama, H. Miyaoka, H. Murakami, M. Nakagawa, M. Namiki, J. Nishimura, S. Ohta, H. Suzuki, F. Tohyama, Y. Tonegawa, N. Yajima, T. Yamagami, H. Yamagishi, and M. D. Yamanaka, Experimental results of polar patrol balloon project in Antarctica, Proc. NIPR Symp. Upper Atmos. Phys., 8, 60-64 (1995)
Fujii, R., R. A. Hoffman, P. C. Anderson, J. D. Craven, M. Sugiura, L. A. Frank, and N. C. Maynard, Electrodynamic parameters in the nighttime sector during auroral substorms, J. Geophys. Res., 99, 6093-6112 (1994)
Fujii, R., S. Nozawa, M. Sato, N. Matuura, T. Ono, A. Brekke, C. Hall, and T. L. Hansen, Comparison between electron spectra calculated from EISCAT electron density profiles and those observed by the DMSP satellites, J. Geomag. Geoelectr., 47, 771-782 (1995)
Fukao, S., Y. Yamamoto, W. L. Oliver, T. Takami, M. D. Yamanaka, M. Yamamoto, T. Nakamura, and T. Tsuda, Middle and upper atmosphere radar observations of ionospheric horizontal gradients produced by gravity waves, J. Geophys. Res., 98, 9443-9451 (1993)
Fukao, S., M. Yamamoto, and R. T. Tsunoda, Quasi-periodic occurrence of mid-latitude E-region field-aligned irregularities revealed by the MU radar, in Low-Latitude Ionospheric Physics (COSPAR Colloquia Series Vol. 7), ed. F. S. Kuo, Pergamon, 177-182 (1994a)
Fukao, S., W. L. Oliver, and M. Yamamoto, MU radar observations of ionospheric gravity-wave packets, dispersion, and horizontal density gradients, in Low-Latitude Ionospheric Physics (COSPAR Colloquia Series Vol. 7), ed. F. S. Kuo, Pergamon, 221-226 (1994b)
Hayakawa, M., K. Ohta, and K. Baba, Wave characteristics of tweek atmospherics deduced from the direction-finding measurement and theoretical interpretation, J. Geophys. Res., 99, 10773-10743 (1994)
Hayakawa, M., K. Ohta, S. Shimakura, and K. Baba, Recent findings on VLF/ELF sferics, J. Atmos. Terr. Phys., 57, 467-477 (1995)
Hoffman, R. A., R. Fujii, and M. Sugiura, Characteristics of the field-aligned current system in the nighttime sector during auroral substorms, J. Geophys. Res., 99, 21303-21325 (1994)
Igarashi, K., S. Kainuma, I. Nishimuta, S. Okamoto, H. Kuroiwa, T. Tanaka, and T. Ogawa, Ionospheric and atmospheric disturbances around Japan caused by the eruption of Mount Pinatubo on 15 June 1991, J. Atmos. Terr. Phys., 56, 1227-1234 (1994)
Igarashi, K., K. Ohtaka, M. Kunitake, T. Tanaka, and T. Ogawa, Development of scanning-beam VHF auroral radar system, Proc. NIPR Symp. Upper Atmos. Phys., 8, 65-69 (1995)
Igi, S., W. L. Oliver, and T. Ogawa, Thermospheric winds over Japan: comparison of ionosonde and radar measurements, J. Geophys. Res., 100, 21323-21326 (1995)
Iwata, A., Y. Tanaka, M. Nishino, and K. Yumoto, Magnetic storm-related energetic electrons penetrating into the magnetosphere, deduced from ground-based measurements of resonant waves, J. Geomag. Geoelectr., 47, 943-952 (1995)
Kimura, I., P. Stubbe, M. T. Rietveld, R. Barr, K. Ishida, Y. Kasahara, S. Yagitani, and I. Nagano, Collaborative experiments by Akebono satellite, Tromso ionospheric heater, and European incoherent scatter radar, Radio Sci., 29, 23-27 (1994)
Kimura, I., A. Hikuma, Y. Kasahara, A. Sawada, M. Kikuchi, and H. Oya, Determination of electron density distributions in the plasmasphere by using wave data observed by Akebono satellite, Adv. Space Res., 15, 2, 103-107 (1995)
Kunitake, M., T. Tanaka, K. Igarashi, S. Yamamoto, H. Maeno, and T. Ogawa, New-type echoes observe with the 50 MHz auroral Doppler radar at Syowa Station, Proc. NIPR Symp. Upper Atmos. Phys., 6, 42-46 (1993)
Kunitake, M., K. Ohtaka, T. Maruyama, M. Tokumaru, A. Morioka, and S. Watanabe, Tomographic imaging of the ionosphere over Japan by the modified truncated SVD method, Ann. Geophys., 13, 1303-1310 (1995)
Maeda, S., and H. Fujiwara, A numerical simulation of thermospheric response to auroral activity--General circulation and atmospheric gravity waves, in Low-Latitude Ionospheric Physics (COSPAR Colloquia Series Vol. 7), ed. F. S. Kuo, Pergamon, 263-273 (1994)
Makita, K., M. Ayukawa, H. Yamagishi, M. Ejiri, and T. Sakanoi, Auroral dynamics in the polar cap region, Proc. NIPR Symp. Upper Atmos. Phys., 8, 7-16 (1995)
Maruyama, T., Non-local theory of ionospheric instability at low latitudes, in Low-Latitude Ionospheric Physics (COSPAR Colloquia Series Vol. 7), ed. F. S. Kuo, Pergamon, 109-120 (1994)
Maruyama, T., Shapes of irregularities in the sporadic E layer producing quasi-periodic scintillations, Radio Sci., 30, 581-590 (1995)
Matuura, N., Mechanisms on the solar wind-magnetosphere interactions: importance of the Svalbard radar, J. Geomag. Geoelectr., 47, 721-733 (1995)
Matuura, N., R. Fujii, Y. Kamide, S. Kokubun, and T. Oguti, Japan-EISCAT collaboration on the Svalbard radar: scientific significance, J. Geomag. Geoelectr., 47, 681-684 (1995)
Minatoya, H., N. Sato, T. Saemundsson, and T. Yoshino, Absence of correlation between periodic pulsating auroras in geomagnetically conjugate areas, J. Geomag. Geoelectr., 47, 583-596 (1995)
Molchanov, O. A., A. P. Nickolaenko, V. A. Rafalsky, A. Yu. Schecotov, and M. Hayakawa, Influence of layered structure of the lower ionosphere on nonmonotonic spectrum behavior of ELF atmospheric noise, Geophys. Res. Lett., 21, 2467-2370 (1994)
Nickolaenko, A. P., V. A. Rafalsky, A. V. Shvets, and M. Hayakawa, A time domain direction finding technique for locating wideband ELF-VLF atmospherics, J. Atmos. Electr., 14, 97-107 (1994)
Nishimura, J., N. Yajima, H. Akiyama, M. Ejiri, R. Fujii, and S. Kokubun, Polar patrol balloon, J. Aircraft, 31, 1264-1267 (1994)
Nishino, M., and Y. Tanaka, Low-latitude VLF hiss associated with the severe magnetic storm on October 19-21, 1989, J. Geomag. Geoelectr., 46, 193-203 (1994)
Nishino, M., Y. Tanaka, T. Oguti, H. Yamagishi, and J. Holtet, Initial observation results with imaging riometer at Ny-Alesund (L=16), Proc. NIPR Symp. Upper Atmos. Phys., 6, 47-61 (1993)
Nozaki, K., and T. Kobayashi, Observation of low-latitude ionospheric irregularities using HF FM/CW radar, in Low-Latitude Ionospheric Physics (COSPAR Colloquia Series Vol. 7), ed. F. S. Kuo, Pergamon, 121-126 (1994)
Ogawa, T., K. Ohtaka, T. Takami, Y. Yamamoto, M. Yamamoto, and S. Fukao, Medium- and large-scale TIDs simultaneously observed by NNSS satellites and the MU radar, in Low-Latitude Ionospheric Physics (COSPAR Colloquia Series Vol. 7), ed. F. S. Kuo, Pergamon, 167-175 (1994)
Ogawa, T., M. Yamamoto, and S. Fukao, Middle and upper atmosphere radar observations of turbulence and movement of mid-latitude sporadic E irregularities, J. Geophys. Res., 100, 12173-12188 (1995)
Ohta, K., A. Shimizu, and M. Hayakawa, The effect of subionospheric propagation on whistlers as deduced from direction finding measurements, Geophys. Res. Lett., 21, 89-92 (1994)
Ohtaka, K., and T. Tanaka, Long term variations of radio auroral activity, Proc. NIPR Symp. Upper Atmos. Phys., 6, 36-41 (1993)
Ohtani, A., T. Ogawa, and K. Igarashi, Latitudinal extent of the f-min winter anomaly region during the DYANA campaign, J. Geomag. Geoelectr., 45, 697-702 (1993)
Okuzawa, T., H. Taguchi, T. Shibata, and S. Itoh, Reconstruction of the images of ionospheric electron density profile using computerized tomography--A preliminary result, J. Geomag. Geoelectr., 47, 1223-1229 (1995)
Oliver, W. L., Y. Yamamoto, S. Fukao, T. Takami, M. Yamamoto, and T. Tsuda, MU radar observations of ionospheric electric fields, J. Geophys. Res., 98, 11615-11627 (1993)
Oliver, W. L., S. Fukao, Y. Yamamoto, T. Takami, M. D. Yamanaka, M. Yamamoto, T. Nakamura, and T. Tsuda, Middle and upper atmosphere radar observations of ionospheric density gradients produced by gravity wave packets, J. Geophys. Res., 99, 6321-6329 (1994)
Oliver, W. L., Y. Yamamoto, M. Sato, T. Takami, and T. Tsuda, MU radar observations of the dispersion relation for ionospheric gravity waves, J. Geophys. Res., 23763-23768 (1995)
Onda, K., and Y. Itikawa, Simulation of particle precipitation and emission processes in electron auroras, Proc. NIPR Symp. Upper Atmos. Phys., 8, 24-36 (1995)
Ono, T., Derivation of energy parameters of precipitating auroral electrons by using the intensity ratios of auroral emissions, J. Geomag. Geoelectr., 45, 455-472 (1993)
Ono, T., and K. Morishima, Energy parameters of precipitating auroral electrons obtained by using photometric observations, Goephys. Res. Lett., 21, 261-264 (1994)
Oyama, K.-I., Verification of IRI plasma temperature at great altitude by satellite data, Adv. Space Res., 14, 12, 105-113 (1994)
Oyama, K.-I., S. Watanabe, and H. Oya, Energetics in the plasma bubble, Adv. Space Res., 13, 1, 293-297 (1993)
Rishbeth, H., and S. Fukao, MU radar observations of the midlatitude thermosphere and ionosphere, J. Geomag. Geoelectr., 47, 621-637 (1995)
Saito, A., T. Iyemori, M. Sugiura, N. C. Maynard, T. L. Aggson, L. H. Brace, M. Takeda, and M. Yamamoto, Conjugate occurrence of the electric field fluctuations in the nighttime midlatitude ionosphere, J. Geophys. Res., 100, 21439-21451 (1995)
Sakamoto, K., Y. Kasahara, and I. Kimura, K-vector determination of whistler mode signals by using amplitude data obtained by a spacecraft borne instrument, IEEE Trans. GRS, 33, 528-534 (1995)
Sawada, A., T. Nobata, Y. Kishi, and I. Kimura, Electron density profile in the magnetosphere deduced from in-situ electron density and wave normal directions of Omega signals observed by the Akebono (EXOS-D) satellite, J. Geophys. Res., 98, 11267-11274 (1993)
Shibata, T., and K. Schlegel, Vertical structure of AGW associated ionospheric fluctuations in the E- and lower F-region observed with EISCAT--A case study, J. Atmos. Terr. Phys., 55, 739-749 (1993)
Shibata, T., K. Inoue, and K. Schlegel, Ion composition in the lower F-region inferred from residuals of ion temperature profile measured with the EISCAT CP1 experiments, J. Geomag. Geoelectr., 47, 879-888 (1995)
Shinagawa, H., Model calculations of the dayside ionosphere of Venus at solar minimum, Geophys. Res. Lett., 20, 2743-2746 (1993a)
Shinagawa, H., A two-dimensional MHD model of the solar wind interaction with the Venus ionosphere, COSPAR Colloquia, 4, 199-202 (1993b)
Shinagawa, H., T. E. Cravens, and D. Wu, The generation of magnetic fields by the polarization electric field in the ionosphere of Venus, J. Geophys. Res., 98, 263-268 (1993)
Shiokawa, K., and K. Yumoto, Global characteristics of particle precipitation and field-aligned electron acceleration during isolated substorms, J. Geophys. Res., 98, 1359-1375 (1993)
Shiokawa, K., K. Yumoto, Y. Tanaka, T. Oguti, and Y. Kiyama, Low-latitude auroras observed at Moshiri and Rikubetsu (L=1.6) during geomagnetic storms on February 26, 27, 29, and May 10, 1992, J. Geomag. Geoelectr., 46, 231-252 (1994)
Shiokawa, K., K. Yumoto, K. Hayashi, T. Oguti, and D. J. McEwen, A statistical study of the motions of auroral arcs in the high-latitude morning sector, J. Geophys. Res., 100, 21979-21985 (1995a)
Shiokawa, K., K. Yumoto, Y. Tanaka, Y. Kiyama, Y. Kamide, and M. Tokumaru, A low-latitude aurora observed at Rikubetsu (L=1.6) during the magnetic storm of September 13, 1993, Proc. NIPR Symp. Upper Atmos. Phys., 8, 17-23 (1995b)
Stauning, P., H. Yamagishi, M. Nishino, and T. J. Rosenberg, Dynamics of cusp-latitude absorption events observed by imaging riometers, J. Geomag. Geoelectr., 47, 823-845 (1995)
Su, Y. Z., K.-I. Oyama, G. J. Bailey, T. Takahashi, and S. Watanabe, Comparison of satellite electron density and temperature measurements at low latitudes with a plasmasphere-ionosphere model, J. Geophys. Res., 100, 14591-14604 (1995)
Takahashi, T., and H. Oya, Large scale structure of the low latitude F-region: plasma bubbles, blobs and longitudinal crest, in Low-Latitude Ionospheric Physics (COSPAR Colloquia Series Vol. 7), ed. F. S. Kuo, Pergamon, 57-62 (1994)
Takahashi, T., H. Oya, and S. Watanabe, Two types of generation mechanism of the equatorial plasma bubbles, in Low-Latitude Ionospheric Physics (COSPAR Colloquia Series Vol. 7), ed. F. S. Kuo, Pergamon, 127-134 (1994)
Takahashi, Y., S. Okano, T. Ono, and H. Fukunishi, Imaging and photometric observations of proton aurora dynamics at Syowa Station, Antarctica, Proc. NIPR Symp. Upper Atmos. Phys., 8, 1-6 (1995)
Tanaka, T., Effects of magnetospheric disturbances on the low-latitude ionosphere, in Low-Latitude Ionospheric Physics (COSPAR Colloquia Series Vol. 7), ed. F. S. Kuo, Pergamon, 15-26 (1994)
Tohyama, F., R. Fujii, M. Ejiri, and N. Yajima, Observations of the geomagnetic field by polar patrol balloon (PPB) experiment in Antarctica, Proc. NIPR Symp. Upper Atmos. Phys., 6, 15-24 (1993)
Tsunoda, R. T., S. Fukao, and M. Yamamoto, On the origin of quasi-periodic radar backscatter from mid-latitude sporadic E, Radio Sci., 29, 349-365 (1994a)
Tsunoda, R. T., S. Fukao, and M. Yamamoto, Modelling of quasi-periodic backscatter from E-region field-aligned irregularities in mid-latitude sporadic E, in Low-Latitude Ionospheric Physics (COSPAR Colloquia Series Vol. 7), ed. F. S. Kuo, Pergamon, 183-194 (1994b)
Ueda, H., S. Goodman, H. Matsumoto, and T. Okuzawa, Influence of density irregularities on high-frequency wave propagation: computer experiments of stimulated emissions, Proc. NIPR Symp. Upper Atmos. Phys., 7, 32-39 (1994)
Watanabe, S., and K.-I. Oyama, Dynamic model and observation of the equatorial ionosphere, Adv. Space Res., 15, 2, 109-112 (1995)
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