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Volume 40, Issue 7
Displaying 1-12 of 12 articles from this issue
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H. Fukunishi1988 Volume 40 Issue 7 Pages 761
Published: 1988
Released on J-STAGE: August 11, 2011
JOURNAL FREE ACCESSDownload PDF (40K) -
Masaki EJIRI, Hiroshi FUKUNISHI, Takayuki ONO, Hisao YAMAGISHI, Takeo ...1988 Volume 40 Issue 7 Pages 763-781
Published: 1988
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSFive sounding rockets were launched from Syowa Station in Antarctica; three in 1984 and two in 1985 by the 25th and 26th wintering parties of Japanese Antarctic Research Expedition. The purpose of the former three was to investigate the causality between auroral particle energy spectra and the auroral light emissions at various stages of polar substorm activities. The latter two aimed at the study of the wave-particle interaction processes on auroral field lines. Scientific objectives and related instrumentations are briefly described. Geomagnetic conditions at the rocket launchings and the flight performances together with outlines of scientific results compared with ground-based observations are presented.View full abstractDownload PDF (8099K) -
Masaki EJIRI, Takayuki ONO, Takasi OGUTI, Nobuyuki YAJIMA, Yoshihiko K ...1988 Volume 40 Issue 7 Pages 783-797
Published: 1988
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSIn order to study the detailed structure of auroral light emissions and related precipitating auroral particles, a new type of a low-light-level visible auroral television (VAT) camera was developed and installed on board three sounding rockets, S-310JA-8, -9 and -10. They were launched in 1984 from Syowa Station, Antarctica, into the three different types of aurora. The VAT had a capability of taking one synthesized still picture (100(H)×101 (V) array) every 4.2sec from the spinning rocket in downward looking. This camera was rotated in an opposite direction to the rocket spin by using an auto-feedback loop circuit with an angular rate sensor, a kind of a rate-gyroscope. Clear auroral images were obtained; the rotational drift rate of the picture was from about 1.1 to 0.1degree/sec in each flight.View full abstractDownload PDF (4095K) -
Masaki EJIRI, Takayuki ONO, Takeo HIRASAWA, Takasi OGUTI1988 Volume 40 Issue 7 Pages 799-815
Published: 1988
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSThree sounding rockets were launched in 1984 from Syowa Station in Antarctica into different types of aurora, designated as AURORA I (an active auroral arc at the substorm expansion phase), II (a stable arc prior to the substorm onset) and III (a diffuse aurora during the recovery phase). A new television camera was used to take an auroral picture, together with the electron spectrometers to measure the energy spectrum of auroral particles. AURORA I showed greater values in both auroral emission and electron density than for AURORA II. In AURORA III, although the auroral emission intensity was much less in comparison with AURORA I, the electron density showed a pronounced enhancement in the D-region and was comparable with the case of AURORA I above the E-region. As for an energy spectrum of auroral electrons, AURORA I and II showed an inverted-V type monoenergetic peak with much higher energy for AURORA I than for AURORA II, whereas AURORA III exhibits a power-law spectrum with a small superposing monoenergetic peak around 0.5keV above 200km in altitude. The television camera showed a dependence of auroral color spectrum on the auroral activity, i. e., the ratio of an apparent emission rate at 427.8nm and an illuminance in a visible range (400 to 800nm) becomes greater for brighter aurora.View full abstractDownload PDF (3143K) -
Fumio TOHYAMA, Masahiro ISHIDO, Hiroshi FUKUNISHI1988 Volume 40 Issue 7 Pages 817-829
Published: 1988
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSAttitudes of the antarctic sounding rockets S-310JA-11 and S-310JA-12 launched from Syowa Station were determined from magnetometer and horizon aspect sensor data. The spin rate, precessional coning angle, and period determined for the S-310JA-11 and S-310JA-12 rockets were 0.57 and 0.59rps, 8.8 and 25.0 degrees, and 308 and 292 seconds, respectively.View full abstractDownload PDF (911K) -
Fumio TOHYAMA, Hiroshi FUKUNISHI, Takao TAKAHASHI, Susumu KOKUBUN, Ryo ...1988 Volume 40 Issue 7 Pages 831-842
Published: 1988
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSThe S-310JA-11 and S-310JA-12 rockets, having a vector magnetometer with high sensitivity (1.8nT) and high sampling frequency (100Hz), were launched into the aurora on May 29 and July 12, 1985, from Syowa Station, Antarctica. The S-310JA-11 rocket penetrated twice quiet arcs, while the S-310JA-12 rocket traversed across intense and active auroral arcs during a large magnetic substorm. In the S-310JA-12 rocket experiment, intense field-aligned currents of 400-600nT were observed when the rocket penetrated an active arc during the descending flight. The magnetometer on board the S-310JA-12 rocket also detected intense electrojet currents with a center at 110km on the upward leg and at 108km on the downward leg. The magnetometer data of the S-310JA-11 rocket showed no distinguished magnetic field variation due to field-aligned current and electrojet.View full abstractDownload PDF (1625K) -
Tadatoshi TAKAHASHI, Hiroshi OYA, Hiroshi FUKUNISHI, Yuzo WATANABE, Hi ...1988 Volume 40 Issue 7 Pages 843-857
Published: 1988
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSElectron density profiles in the auroral ionosphere were measured by the impedance probe on board the S-310JA-11 and -12 rockets. The S-310JA-11 rocket was launched from Syowa Station into quiet auroral arcs (-2kR) on May 29, 1985, while the S-310JA-12 rocket was launched into active arcs (-14kR) on July 12, 1985. The S-310JA-11 data showed a typical altitude profile of the electron number density in an auroral arc under geomagnetically quiet condition, with a peak number density of 2×105cm-3 at 115km altitude. The S-310JA-12 data, which was obtained in bright auroras in the expansion phase of a substorm, showed a peak density of 1.2×106cm-3 at 101km altitude. On the downleg of the S-310JA-12 rocket, strong irregularities in the electron density distribution were observed at F region height in the active auroral arc region. It is pointed out that the ionospheric structure in the E region is produced mainly by precipitating particles while that in the F region seems to be largely affected by dynamical processes.View full abstractDownload PDF (1154K) -
Hirotaka MORI, Eiichi SAGAWA, Tadahiko OGAWA, Toshio OGAWA, Hisao YAMA ...1988 Volume 40 Issue 7 Pages 859-869
Published: 1988
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSThe S-310JA-12 rocket was launched toward geomagnetic north from Syowa Station, Antarctica, during a strong substorm. A Faraday cup aboard the rocket measured electron density and its fluctuations up to 5kHz, together with total flux of electrons having energies above 105eV, while a pair of probes measured DC electric fields and electric field fluctuations in the 5-220Hz range. During ascent, the Faraday cup detected burst-like fluctuations between 140km and 200km in altitude, which are believed to have been artificially generated around the rocket. Around the altitude of 220km, quasi-sinusoidal waves of about 150Hz were observed by both instruments. From the cross-correlation analysis, they are found to be right-handed, circularly or elliptically poralized waves. During descent, the rocket passed through a highly active aurora and observed strong ELF fluctuations. The Faraday cup measurements suggest that the rocket was charged to several volts by the precipitating electrons.View full abstractDownload PDF (1066K) -
Hisao YAMAGISHI, Hiroshi MIYAOKA, Masaki EJIRI, Eiichi SAGAWA, Nobuyuk ...1988 Volume 40 Issue 7 Pages 871-886
Published: 1988
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSEnergy spectra and pitch angle distributions of auroral electrons were obtained by means of two sounding rockets launched respectively into stable auroral arcs in geomagnetically quiet condition, and into active auroral arcs during the expansion phase of a substorm. These rockets were launched from Syowa Station, Antarctica in the austral winter in 1985.
It was found that the observed energy spectra of downward electrons show a plateau extending from about 1keV to several keV in the center of an auroral arc, while they have a mono-energetic peak at the edge, or just outside an auroral arc. This feature suggests that strong wave-particle interaction processes are occurring on auroral field lines.
The pitch angle distribution of auroral electrons at the mono-energetic peak was isotropic in the range from 0° to 90° (0° is upward along the magnetic field line), and was almost isotropic in the energy below the peak. The former feature suggests acceleration of auroral electrons at high altitude, and the latter feature is attributable to secondary electrons produced by auroral electrons.
Just outside an auroral arc, the peak energy decreased with the distance from the arc. This feature can be considered to be an inverted-V structure of precipitating electrons observed at the rocket altitude.View full abstractDownload PDF (6291K) -
Eiichi SAGAWA, Hisao YAMAGISHI, Hiroshi MIYAOKA, Nobuyuki KAYA, Toshif ...1988 Volume 40 Issue 7 Pages 887-904
Published: 1988
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSAn instrument has been developed for observing high frequency modulations or fluctuations of auroral electron flux up to several magahertzs. The instrument utilizes on-board processing hardware for calculating auto-correlation functions (ACFs) of particle flux measured by any type of particle detector which outputs a series of pulses. The instrument is capable of measuring flux modulations in three frequency ranges, i. e., 1.5-100Hz, 0.06-8kHz and 0.03-4MHz, respectively. Two rocket observations by using the instrument were carried out as part of low energy auroral electron experiments on board the S-310JA-11 and -12 rockets which were launched into the Antarctic auroral ionosphere. Preliminary analyses of the rocket data indicate that, under relatively quiet conditions (S-310JA-11), the auroral electrons are almost uniform in the high and medium frequency ranges. Results from another rocket experiment (S-310JA-12) conducted under highly active aurora conditions show low frequency modulations (less than 40Hz) of electron flux associated with regions of a strong electron precipitation, in particular, with edges of the regions.View full abstractDownload PDF (5471K) -
Isamu NAGANO, Eiko YAMAMOTO, Kozo HASHIMOTO, Iwane KIMURA, Hisao YAMAG ...1988 Volume 40 Issue 7 Pages 905-921
Published: 1988
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSElectromagnetic waves in the VLF range associated with auroral hiss were observed by the S-310JA-11 and -12 rockets launched from Syowa Station into quiet auroral arcs and breakup auroras, respectively. The altitude profile of electric field intensity observed by the S-310JA-12 rocket in the frequency range less than 5kHz showed a distinct peak at an altitude of 90km. The source location of the auroral hiss has been estimated so that the observed altitude profile of the hiss intensity, particularly around the altitude of 90km, coincides with the altitude profile calculated using the full wave analysis. It was found that the auroral hiss is most likely to be generated at an altitude about 700km. The intensity of auroral hiss around the altitude of 200km at a frequency of 4kHz observed by the rocket was 4.3×10-5V/m/√Hz, which is much stronger, by about 50dB, than that of auroral hiss observed on the ground at Syowa Station. This means that the k-vector direction of auroral hiss observed on the rocket is outside the transmission cone.View full abstractDownload PDF (3409K) -
Results from Antarctic Rocket ObservationsAkira MORIOKA, Hiroshi OYA, Hiroshi MIYAOKA, Takayuki ONO, Takahiro OB ...1988 Volume 40 Issue 7 Pages 923-937
Published: 1988
Released on J-STAGE: September 14, 2010
JOURNAL FREE ACCESSPlasma wave observations using the sounding rockets, S-310JA-11 and S-310JA-12 have disclosed the following new aspects of wave-particle interaction processes in the auroral ionosphere:
1) generation of intense Z-mode waves by auroral particles through the inverse Landau damping,
2) confirmation of the leaked components of auroral kilometric radiation, and
3) detection of naturally generated electrostatic electron cyclotron harmonic (ESCH) waves in the frequency range lower than the local electron cyclotron frequency.
It is pointed out that Z-mode waves in the auroral region have a very important role because the waves are easily generated being coupled with the particle precipitation. The leaked component of AKR is an important manifestation of the mode conversion processes. The generation of ESCH waves are associated with the nonlinear wave-particle interaction. The newly detected ESCH wave phenomena correspond to n=0 case of the fDn emissions.View full abstractDownload PDF (2559K)
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