Articles | Volume 18, issue 9
Ann. Geophys., 18, 1224–1230, 2000

Special issue: IXe EISCAT

Ann. Geophys., 18, 1224–1230, 2000

  30 Sep 2000

30 Sep 2000

Frequency dependent power fluctuations: a feature of the ESR system or physical?

Y. Ogawa1, F. Forme2, and S. C. Buchert1 Y. Ogawa et al.
  • 1Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
  • 2CETP-Universite Versailles St-Quentin en Yvelines 10-12, Av. de l'Europe, 78140 Velizy, France

Abstract. The k-dependence of the received power in high signal-to-noise ratio (SNR) conditions, occurring for naturally enhanced ion-acoustic lines (NEIALs) and for real satellites, is investigated by using the EISCAT Svalbard Radar (ESR), where the data are recorded in eight separate channels using different frequencies. For the real satellites we find large variations of the relative powers from event to event, which is probably due to a different number of pulses catching the satellite over the integration period. However, the large power difference remains unexpected in one case. Over short time scale (< 10 s) the relative power difference seems to be highly stable. For most NEIAL events the differences between channels are within noise level. In a few cases variations of the relative power well above both the estimated and expected 1-sigma level occur over a signal preintegrated profile. We thus suggest that the frequency dependence of the power in NEIAL events has its origin in the scattering medium itself as the most plausible explanation.

Key words: Ionosphere (auroral ionosphere; plasma waves and instabilities; instruments and techniques)

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