Ionospheric feedback instability and substorm development

We report on ground magnetic and optical observations performed during an ionospheric heating experiment at the High Frequency Active Auroral Research Program (HAARP) facility in Alaska on 29 October 2008. The experiment was aimed at generation of large‐amplitude ULF electromagnetic waves by trigger...

Full description

Saved in:
Bibliographic Details
Published in:Journal of Geophysical Research. A. Space Physics 2010-07, Vol.115 (A7), p.n/a
Main Authors: Streltsov, A. V., Pedersen, T. R., Mishin, E. V., Snyder, A. L.
Format: Article
Language:English
Subjects:
Atmospheric sciences
Auroral arcs
Auroral research
Auroral zones
Dynamic stability
Earth sciences
Earth, ocean, space
Electric arcs
Electric fields
Electromagnetic radiation
Electromagnetic waves
Exact sciences and technology
Experiments
Feedback
Geomagnetic substorms
Geomagnetism
Geophysics
Ground-based observation
Instability
Ionosphere
ionospheric feedback instability
Ionospheric heating
Magnetic fields
Magnetism
Magnetometers
Optical observations
Plasma density
substorm
Transmitters
ULF waves
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We report on ground magnetic and optical observations performed during an ionospheric heating experiment at the High Frequency Active Auroral Research Program (HAARP) facility in Alaska on 29 October 2008. The experiment was aimed at generation of large‐amplitude ULF electromagnetic waves by triggering and facilitating development of the ionospheric feedback instability (IFI) in the region adjacent to a bright auroral arc. In this region the downward/return magnetic field‐aligned current decreases plasma density and enhances the electric field in the ionosphere. A combination of these two effects creates favorable conditions for the instability. The experiment occurred during a period of substorm activity, but effects from the HAARP transmitter were not sufficiently intense to be detected against the background of strong natural oscillations occurring farther north from the HAARP site. Thus the experiment did not provide concrete evidence that heating of the ionosphere with powerful HF transmitters can affect IFI development or generate intense ULF electromagnetic waves. However, during the experiment ground‐based magnetometers in Alaska and Canada detected large‐amplitude ULF waves in regions where the substorm onset auroral arcs interacted with the ionosphere. The frequencies of these waves closely matched frequencies predicted by simulations of IFI for these particular geophysical conditions. These observations support the hypothesis that geomagnetic substorms, the corresponding dynamics of discrete auroral arcs, and the ionospheric feedback instability are closely connected phenomena.
ISSN:0148-0227
2169-9380
2156-2202
2169-9402
DOI:10.1029/2009JA014961