The 3‐D Distribution of Artificial Aurora Induced by HF Radio Waves in the Ionosphere

We present 3‐D excitation rate estimates of artificial aurora in the ionospheric F layer, induced by high‐frequency radio waves from the European Incoherent Scatter heating facility. Simultaneous imaging of the artificial aurora was done with four separate Auroral Large Imaging System stations, perm...

Full description

Saved in:
Bibliographic Details
Published in:Journal of geophysical research. Space physics 2019-04, Vol.124 (4), p.2992-3006
Main Authors: Kvammen, A., Gustavsson, B., Sergienko, T., Brändström, U., Rietveld, M., Rexer, T., Vierinen, J.
Format: Article
Language:English
Subjects:
Activation
Altitude
Atmosphere
Atomic oxygen
aurora
Auroral emissions
EISCAT
Electron acceleration
Emission lines
F region
heating
High frequencies
Imaging
Incoherent scattering
Inspection
Ionosphere
Matematikk og Naturvitenskap: 400
Mathematics and natural science: 400
Medical imaging
Oxygen
Plasma interactions
Radio waves
reconstruction
Tomography
Upper atmosphere
VDP
Wavelengths
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 present 3‐D excitation rate estimates of artificial aurora in the ionospheric F layer, induced by high‐frequency radio waves from the European Incoherent Scatter heating facility. Simultaneous imaging of the artificial aurora was done with four separate Auroral Large Imaging System stations, permitting tomography‐like 3‐D auroral reconstruction of the enhanced atomic oxygen emissions at 6,300, 5,577, and 8,446 Å. Inspection of the 3‐D reconstructions suggests that the distribution of energized electrons is less extended in altitude than predicted by transport calculations of electrons accelerated to 2–100 eV. A possible reason for this discrepancy is that high‐frequency pumping might induce an anisotropic distribution of energized electrons. Plain Language Summary Auroral lights can be artificially generated by transmitting high‐frequency radio waves with high power into the upper atmosphere. In this article, we use multiple viewpoint imaging of artificially produced aurora to estimate the 3‐D distribution of the auroral lights by employing tomography‐like techniques. The 3‐D distribution is estimated in the red, green, and infrared auroral emission lines with wavelengths of 630.0, 557.7, and 844.6 nm, respectively. These emissions are excited by energetic electrons, which have been accelerated through interaction processes between the transmitted radio waves and plasma in the upper atmosphere, at an altitude of about 220–250 km. We observe that the estimated 3‐D auroral distributions are less extended in altitude than indicated by previous theoretical work. A possible reason for this disagreement is that the radio wave‐plasma interaction processes might lead to a direction dependent electron acceleration. Key Points The first 3‐D estimates of induced emission at 8,446 Å are presented along with 3‐D estimates of the enhanced emission at 6,300 and at 5,577 Å The altitude distribution of the resulting excitation rates is inconsistent with excitation rate predictions We observe that the emission enhancements are strongly dependent on the pump frequency proximity to the double resonance
ISSN:2169-9380
2169-9402
2169-9402
DOI:10.1029/2018JA025988