Generation of extremely low frequency radiation by ionospheric electrojet modulation using powerful high-frequency heating waves

Spencer Kuo, S. H. Lee

Research output: Contribution to journalArticle

Abstract

Using amplitude-modulated high-frequency (HF) heating waves for electron heating, the conductivity of plasma and thus the embedded electrojet currents in high-latitude ionosphere can be modulated accordingly to set up the ionospheric antenna current for extremely low frequency (ELF) wave generation. Electron heating is hampered by inelastic collisions of electrons with neutral particles (mainly due to vibration excitation of N2), which cause the induced modulation current to remain at a low level. However, this inelastic collision loss rate drops rapidly to a low value in the energy regime from 3.5 to 6 eV. Thus, as the heating power exceeds a critical level, electron heating suddenly reaches an unexpected high level, resulting to a near step increase (of about 5 to 8 dB depending on the modulation waveform and frequency) in the spectral intensity of ELF radiation. The dependency of this critical HF heating-wave power on the modulation frequency is determined for three heating wave modulation forms: (1) rectangular wave, (2) sine wave, and (3) half-wave rectified wave.

Original languageEnglish (US)
Pages (from-to)488-492
Number of pages5
JournalRadio Science
Volume39
Issue number1
StatePublished - Jan 2004

Fingerprint

electrojets
extremely low frequencies
electrojet
ionospherics
Modulation
heating
modulation
Radiation
Heating
radiation
electron
Electrons
inelastic collisions
electrons
collision
wave power
Wave power
wave generation
critical frequencies
Ionosphere

Keywords

  • Amplitude-modulation schemes
  • Electrojet current modulation
  • ELF radiation
  • HF heating experiments

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Atmospheric Science
  • Computers in Earth Sciences
  • Computer Networks and Communications
  • Instrumentation

Cite this

Generation of extremely low frequency radiation by ionospheric electrojet modulation using powerful high-frequency heating waves. / Kuo, Spencer; Lee, S. H.

In: Radio Science, Vol. 39, No. 1, 01.2004, p. 488-492.

Research output: Contribution to journalArticle

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AB - Using amplitude-modulated high-frequency (HF) heating waves for electron heating, the conductivity of plasma and thus the embedded electrojet currents in high-latitude ionosphere can be modulated accordingly to set up the ionospheric antenna current for extremely low frequency (ELF) wave generation. Electron heating is hampered by inelastic collisions of electrons with neutral particles (mainly due to vibration excitation of N2), which cause the induced modulation current to remain at a low level. However, this inelastic collision loss rate drops rapidly to a low value in the energy regime from 3.5 to 6 eV. Thus, as the heating power exceeds a critical level, electron heating suddenly reaches an unexpected high level, resulting to a near step increase (of about 5 to 8 dB depending on the modulation waveform and frequency) in the spectral intensity of ELF radiation. The dependency of this critical HF heating-wave power on the modulation frequency is determined for three heating wave modulation forms: (1) rectangular wave, (2) sine wave, and (3) half-wave rectified wave.

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