Ionospheric modifications in high frequency heating experiments
- Department of Electrical and Computer Engineering, Polytechnic School of Engineering, New York University, 5 MetroTech Center, Brooklyn, New York 11201 (United States)
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.
- OSTI ID:
- 22408007
- Journal Information:
- Physics of Plasmas, Vol. 22, Issue 1; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
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