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High Bandwidth Measurements of Auroral Langmuir Waves with Multiple Antennas
  • Chrystal Moser,
  • James Labelle,
  • Iver Cairns
Chrystal Moser
Dartmouth College

Corresponding Author:[email protected]

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James Labelle
Dartmouth College
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Iver Cairns
University of Sydney
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Abstract

The High-Bandwidth Auroral Rocket (HIBAR) was launched from Poker Flat, Alaska on January 28, 2003 at 07:50 UT towards an apogee of 382 km in the night-side aurora. The flight was unique in having three high-frequency (HF) receivers using multiple antennas parallel and perpendicular to the ambient magnetic field, as well as very low frequency (VLF) receivers using antennas perpendicular to the magnetic field. These receivers observed five short-lived Langmuir wave bursts lasting from 0.1–0.2 s, consisting of a thin plasma line with frequencies in the range of 2470–2610 kHz that had an associated diffuse feature occurring 5–10 kHz above the plasma line. Both of these waves occurred slightly above the local plasma frequency with amplitudes between 1–100 μV/m. The ratio of the parallel to perpendicular components of the plasma line and diffuse feature were used to determine the angle of propagation of these waves with respect to the background magnetic field. These angles were compared to the theoretical Z-infinity angle that these waves would resonate at, and found to be comparable. The VLF receiver detected auroral hiss at frequencies between 5–10 kHz throughout the flight from 100–560 s, a frequency matching the difference between the plasma line and the diffuse feature. A dispersion solver and associated frequency- and wavevector-matching conditions were employed to determine if the diffuse features could be generated by a nonlinear wave-wave interaction of the plasma line with the lower frequency auroral hiss waves. The results show that this interpretation is plausible.
22 Apr 2022Published in Annales Geophysicae volume 40 issue 2 on pages 231-245. 10.5194/angeo-40-231-2022