All issues
Successor
Volume 32 (1980)
- Issue 12 Pages 721-
- Issue 11 Pages 671-
- Issue 10 Pages 585-
- Issue 9 Pages 507-
- Issue 8 Pages 431-
- Issue 7 Pages 365-
- Issue 6 Pages 309-
- Issue 5 Pages 265-
- Issue 4 Pages 181-
- Issue 3 Pages 129-
- Issue 2 Pages 67-
- Issue 1 Pages 1-
- Issue Supplement3 Pag･･･
- Issue Supplement2 Pag･･･
- Issue Supplement1 Pag･･･
Volume 47, Issue 6
Displaying 1-5 of 5 articles from this issue
- |<
- <
- 1
- >
- >|
-
Yoshiya Kasahara, Ken-ichiro Yoshida, Toshio Matsuo, Iwane Kimura, Tos ...1995 Volume 47 Issue 6 Pages 509-525
Published: June 20, 1995
Released on J-STAGE: April 03, 2007
JOURNAL FREE ACCESSV-shaped hiss and saucer emission observed by the Akebono satellite in the auroral region in the altitude range between 3, 000 km and 5, 000 km were studied on their wave normal directions using 5 components of electric and magnetic field wave data by Phillips-Tikhonov regularization method. It was found that the V-shaped hiss come down to the spacecraft and their azimuthal direction of wave normal is anti-symmetric with respect to the location of V-shaped frequency minimum. Ray tracing study is made to see how the frequency versus time characteristics and wave normal direction of the emissions should be at the satellite level. The results by ray tracing shows good agreement with the observation, under the assumption that the initial wave normal direction is circularly symmetric around the magnetic field, with the resonance cone angle.View full abstractDownload PDF (2935K) -
D. J. McEwen, D. P. Harris, J. W. MacDougall, I. F. Grant1995 Volume 47 Issue 6 Pages 527-537
Published: June 20, 1995
Released on J-STAGE: April 03, 2007
JOURNAL FREE ACCESSEstablishment of a polar observatory at Eureka, Canada in 1991 has permitted studies of F-layer ionization patches drifting over the north magnetic pole, using a multi-channel photometer and a digital ionosonde. Optical characteristics of two typical patches are shown. A case study of a sequence of several patches observed on February 17, 1993 is reported. Their optical intensities as determined from 630 and 558 nm meridian photometer scans averaged 200 R and 50 R respectively above airglow background. Their drift velocities through zenith, as measured by a digital ionosonde (CADI), averaged about 0.3 km/s while their bulk motion as seen optically was somewhat greater. The first 3 patches of the sequence, from 0945 to 1010 UT, moved generally in an antisunward direction while three immediately following, from 1015 to 1100 UT, had a velocity component in the dawn to dusk direction with a velocity vector rotated a full 90° from the earlier motions.View full abstractDownload PDF (2193K) -
G. V. Vergasova, E. S. Kazimirovsky, V. D. Kokourov, V. F. Petruchin1995 Volume 47 Issue 6 Pages 539-549
Published: June 20, 1995
Released on J-STAGE: April 03, 2007
JOURNAL FREE ACCESSThe horizontal wind field in the ionospheric D-region belongs to important parameter related to ionospheric radio wave absorption. The analysis of continuous ionospheric vertical radio sounding and wind measurements by the spaced receiver method in low-frequency range (Irkutsk, East Siberia 1975-1991) is applicated to define the possible coupling of absorption and dynamics in their seasonal and year-to-year dependence. For the analysis we used parameter dfmin =fmin -fmin median, prevailing winds, amplitudes and phases of semidiumal tides for zonal and meridional winds. For some seasons there are significant but changeable correlations between dfmin and prevailing wind. In most cases especially in winter the changes of wind outstrip the changes of absorption. Quasi-periodic fluctuations with planetary wave periods (18-30 days) exist in winter for both. The periodicity close to 27 days (26-30 days) exists for all seasons and all parameters. Application of correloperiodogram analysis reveals the response of ionospheric absorption to the dynamical processes, quantitatively depending on the solar and geomagnetic activity.View full abstractDownload PDF (2056K) -
Hideo Tsunakawa1995 Volume 47 Issue 6 Pages 551-576
Published: June 20, 1995
Released on J-STAGE: April 03, 2007
JOURNAL FREE ACCESSA simple deconvolution method of the post-depositional DRM (detrital remanent magnetization) is proposed and examined using the synthetic data. Assuming the exponential fixing function of magnetic moments in sediments, the original field is expressed by a simple function of the convolved field. This leads us to the deconvolution of the post-depositional DRM if the fixing depth is known. In general the fixing depth is not given, so that the problem becomes complicated. However, adopting a few reasonable assumptions, the deconvolution is performed as a nonlinear problem with the fixing depth being an unknown parameter. Consequently the original field including the relative field intensity can be estimated from the direction data sets with the new method.View full abstractDownload PDF (3938K) -
Munetoshi Tokumaru1995 Volume 47 Issue 6 Pages 577-582
Published: June 20, 1995
Released on J-STAGE: April 03, 2007
JOURNAL FREE ACCESSDynamic spectrum observations of the Jovian decametric radiation (JDR) have been carried out since 1993 at the Wakkanai Radio Observatory using a new radiospectrograph system, which covers with a frequency range from 20 to 40 MHz. The Faraday effect in JDR spectra is analyzed for two kinds of JDR events; emissions from lo-related (lo-A) source and those from non lo-related source. A significant excess of the Faraday rotation to the terrestrial contribution is disclosed by the comparison with satellite beacon measurements taken simultaneously at Wakkanai. This result suggests that the Faraday effect by the Jovian plasma cannot be neglected for both Io-A and non Io-A emissions.View full abstractDownload PDF (1329K)
- |<
- <
- 1
- >
- >|