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Title: Ionospheric modifications in high frequency heating experiments

Featured observations in high-frequency (HF) heating experiments conducted at Arecibo, EISCAT, and high frequency active auroral research program are discussed. These phenomena appearing in the F region of the ionosphere include high-frequency heater enhanced plasma lines, airglow enhancement, energetic electron flux, artificial ionization layers, artificial spread-F, ionization enhancement, artificial cusp, wideband absorption, short-scale (meters) density irregularities, and stimulated electromagnetic emissions, which were observed when the O-mode HF heater waves with frequencies below foF2 were applied. The implication and associated physical mechanism of each observation are discussed and explained. It is shown that these phenomena caused by the HF heating are all ascribed directly or indirectly to the excitation of parametric instabilities which instigate anomalous heating. Formulation and analysis of parametric instabilities are presented. The results show that oscillating two stream instability and parametric decay instability can be excited by the O-mode HF heater waves, transmitted from all three heating facilities, in the regions near the HF reflection height and near the upper hybrid resonance layer. The excited Langmuir waves, upper hybrid waves, ion acoustic waves, lower hybrid waves, and field-aligned density irregularities set off subsequent wave-wave and wave-electron interactions, giving rise to the observed phenomena.
Authors:
 [1]
  1. Department of Electrical and Computer Engineering, Polytechnic School of Engineering, New York University, 5 MetroTech Center, Brooklyn, New York 11201 (United States)
Publication Date:
OSTI Identifier:
22408007
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 1; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ABSORPTION; AIRGLOW; CUSPED GEOMETRIES; DECAY INSTABILITY; EMISSION; EXCITATION; HEATING SYSTEMS; HYBRID RESONANCE; INTERACTIONS; ION ACOUSTIC WAVES; IONIZATION; LOWER HYBRID HEATING; PARAMETRIC INSTABILITIES; REFLECTION; SHORT WAVE RADIATION; SPREAD F; TAIL ELECTRONS; TWO-STREAM INSTABILITY