Electron density and plasma waves in mid-latitude sporadic-E layer observed during the SEEK-2 campaign

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Wakabayashi , M. ; Ono , T. ; Mori , H. ; Bernhardt , P. A. (2005)
  • Publisher: European Geosciences Union
  • Journal: Annales Geophysicae (issn: 0992-7689, eissn: 1432-0576)
  • Related identifiers: doi: 10.5194/angeo-23-2335-2005
  • Subject: Geophysics. Cosmic physics | Q | [ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences | [ SDU.OCEAN ] Sciences of the Universe [physics]/Ocean, Atmosphere | Science | Physics | QC1-999 | QC801-809

International audience; The SEEK-2 campaign was carried out over Kyushu Island in Japan on 3 August 2002, by using the two sounding rockets of S310-31 and S310-32. This campaign was planned to elucidate generation mechanisms of Quasi-Periodic Echoes (QPEs) associated with mid-latitude sporadic-<i>E</i> (<i>E<sub>s</sub></i>) layers. Electron number densities were successfully measured in the <i>E<sub>s</sub></i> layers by using the impedance probe on board two rockets. The plasma waves in the VLF and ELF ranges were also observed on board the S310-32 rocket. Results of electron density measurement showed that there were one or two major peaks in the <i>E<sub>s</sub></i> layers along the rockets' trajectories near the altitude of about 10km. There were some smaller peaks associated with the main <i>E<sub>s</sub></i> layers in the altitude range from 90 to 120 km. These density peaks were distributed in a very large extent during the SEEK-2 campaign. The <i>E<sub>s</sub></i> layer structure is also measured by using the Fixed Bias Probe (FBP), which has a high spatial resolution of several meters (the impedance probe has an altitude resolution of about 400 m). The comparison with the total electron content (TEC) measured by the Dual Band Beacon revealed that the <i>E<sub>s</sub></i> layer was also modulated in the horizontal direction with the scale size of 30?40 km. It was shown that the QP echoes observed by the ground-based coherent radar come from the major density peak of the <i>E<sub>s</sub></i> layer. The plasma wave instrument detected the enhancement of VLF and ELF plasma waves associated with the operation of the TMA release, and also with the passage of the <i>E<sub>s</sub></i> layers.<br><br> <b>Keywords.</b> Ionosphere (Ionospheric irregularities; Midlatitude ionosphere; Plasma temeperature and density)
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