Phase relation between Pi2‐associated ionospheric Doppler velocity and magnetic pulsations observed at a midlatitude MAGDAS station

  1. Department of Earth and Planetary Sciences, Kyushu University, Fukuoka, Japan
  2. Space Environment Research Center, Kyushu University, Fukuoka, Japan
  3. Kagoshima National College of Technology, Kagoshima, Japan
  4. National Institute of Information and Communications Technology, Koganei, Japan
  5. Institute of Cosmophysical Research and Radiowaves Propagation, Far Eastern Branch, Russian Academy of Sciences, Kamchatka Region, Russia

 We examined the correlation between nighttime Pi2 pulsations detected
simultaneously by a frequency modulated continuous wave (FM‐CW) (HF) radar and by a
ground magnetometer, both located at a midlatitude (L = 2.05) Magnetic Data Acquisition
System station. Eighty‐three Pi2 events were observed during the 43 day period from
23 September 2006 to 4 November 2006. The variations of the ground magnetic H
component and ionospheric Doppler velocity (V*) exhibited high coherence for 80% of
the 83 Pi2 events, for about a half of which the H and V* variations have the same
dominant frequency. For such events, V* led H by 90° in phase, in the midnight sector of
2230–0300 LT. The average Ey (east‐west electric field) amplitude derived from V* is
0.27 mV/m. The 90° phase delay was not found for the five events that were observed near
dusk and dawn. The phase relation of H and V* for Pi2s in the midnight sector may be
explained in terms of the radial standing structure of compressional waves, i.e., cavity
mode oscillation.
 

A. Ikeda, K. Yumoto, T. Uozumi, M. Shinohara, K. Nozaki, A. Yoshikawa, V. V. Bychkov, B. M. Shevtsov Phase relation between Pi2‐associated ionospheric Doppler velocity and magnetic pulsations observed at a midlatitude MAGDAS station // Journal of Geophysical Research. 2010. Vol. 115/A02215, doi:10.1029/2009JA014397.