Scex 3 Observations of Hf Z-Mode Emissions from the Aurora
- Robert L. Lysak
Published Online: 18 MAR 2013
Copyright 1993 by the American Geophysical Union
Auroral Plasma Dynamics
How to Cite
Goerke, R.T., Kellogg, P.J., Bale, S.D., Monson, S.J., Anderson, H.R., Potter, D.W., Szuszczewicz, E.P. and Earle, G.D. (1993) Scex 3 Observations of Hf Z-Mode Emissions from the Aurora, in Auroral Plasma Dynamics (ed R. L. Lysak), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM080p0275
- Published Online: 18 MAR 2013
- Published Print: 1 JAN 1993
Print ISBN: 9780875900391
Online ISBN: 9781118664001
- Space plasmas—Plasma dynamics
We have observed moderately strong HF (high frequency ≈4 MHz) plasma waves with amplitudes in excess of .1 mV/m(Hz)1/2 at frequencies slightly less than the ambient plasma frequency and about 2 to 3 times the electron cyclotron frequency. These observations coincide with in situ measurements of broad band low energy (10 eV to 600 eV) auroral electrons and ground-based observations of auroral luminosity. These results were obtained from the rocket-borne experiment SCEX 3 (Several Compatible Experiments Using a Rocket-Borne Accelerator), NASA Flight 39.002 UE, launched February 1, 1990 from Poker Flat Research Range.
The frequency and intensity of the HF emissions are modulated at the spin period of the spacecraft in such a way that they appear like saucers on frequency-time spectrogram. This indicates that the source of these observations is a directional wave. If these waves are transverse (electromagnetic), then the k vector points in the north/south direction, which is consistent with an auroral source. Due to the lack of an observable interference pattern, we assume the waves have a wavelength that is much larger than the antenna length (2 m). These waves are seen consistently above the Z cutoff and persist over a region of ˜100 km which is suggestive of transverse electromagnetic waves. Other features of the aurora which produced these emissions will be presented and discussed.