X-mode suppression of artificial E region field-aligned plasma density irregularities
Article first published online: 24 MAR 2011
Copyright 2011 by the American Geophysical Union.
Volume 46, Issue 2, April 2011
How to Cite
2011), X-mode suppression of artificial E region field-aligned plasma density irregularities, Radio Sci., 46, RS2010, doi:10.1029/2010RS004551., , and (
- Issue published online: 24 MAR 2011
- Article first published online: 24 MAR 2011
- Manuscript Accepted: 12 JAN 2011
- Manuscript Revised: 30 DEC 2010
- Manuscript Received: 2 NOV 2010
- ionospheric modifications;
- thermal parametric instability
 Ionospheric modification experiments have been performed at the High frequency Active Auroral Research Program involving the creation and suppression of artificial field-aligned density irregularities (AFAIs) using O-mode and X-mode continuous wave emissions, respectively. The emission frequencies were offset so that the O-mode upper hybrid interaction height nearly matched the X-mode reflection height in the ionospheric E region. AFAIs created by O-mode heating were observed using a 30 MHz coherent scatter radar imager. Simultaneous X-mode heating was found to suppress the AFAI intensity and increase the threshold power for excitation by approximately a factor of 5 in our experiments. The effects are attributed in part to the broadening of the upper hybrid interaction region and in part to increased O-mode absorption, which reduces the amplitude of the standing wave pattern in that region. Preliminary estimates based on local calculations suggest that the electron temperature in the E region was increased by a factor of about 1.6 in these experiments.