High altitude large-scale plasma waves in the equatorial electrojet at twilight
Jicamarca radar observations of a new class of large-scale plasma waves in the equatorial electrojet (EEJ) are presented and characterized. The study is based on long-term (204 days), single-baseline interferometry observations made in 2003 using a low-power radar mode, also known as J...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2004-12-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/22/4071/2004/angeo-22-4071-2004.pdf |
| Summary: | Jicamarca radar observations of a new class of large-scale plasma
waves in the equatorial electrojet (EEJ) are presented and
characterized. The study is based on long-term (204 days),
single-baseline interferometry observations made in 2003 using a
low-power radar mode, also known as JULIA mode, along with a few
hours of observations made in an aperture synthesis imaging mode.
The large-scale waves are found to occur at high altitudes in the
E-region, mainly between 120 and 140km, around twilight
(between 18:30 and 20:00 LT), with durations of a few minutes to an
hour. In our long-term observations, these large-scale waves occur
very often (between 1 and 5 out 10 nights), drift westward
(~70 ms<sup>–1</sup>), exhibit very narrow spectral widths, and have
both positive and negative Doppler shifts. The imaging results
show that the large-scale waves occur along tilted bands that
sweep westward and downward (~30–60ms<sup>–1</sup>), with a horizontal
separation between bands of about 10–15km. The cause of the
waves remains unknown.
<br><br><b>Key words.</b> Ionosphere (ionospheric irregularities; equatorial
ionosphere; instruments and techniques) |
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| ISSN: | 0992-7689 1432-0576 |