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HF‐driven currents in the polar ionosphere
Author(s) -
Papadopoulos K.,
Gumerov N. A.,
Shao X.,
Doxas I.,
Chang C. L.
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl047368
Subject(s) - electrojet , ionosphere , geophysics , physics , ionospheric heater , equatorial electrojet , antenna (radio) , polar , electric field , computational physics , magnetic field , earth's magnetic field , astronomy , telecommunications , quantum mechanics , computer science
Polar ionospheric heaters have generated ULF/ELF/VLF waves by modulating the auroral electrojet at D/E region altitudes. We present theoretical/computational results indicating that modulated F‐region HF heating can generate ionospheric currents even in the absence of electrojet currents. The ELF currents are driven in a two‐step process. First, the pressure gradient associated with F‐region electron heating drives a local diamagnetic current. This acts as an antenna to inject Magneto‐Sonic (MS) waves in the ionospheric plasma. Second, the electric field of the magneto‐sonic wave drives Hall currents when it reaches the E region of the ionosphere. The Hall currents act as a secondary antenna that injects waves in the Earth‐Ionosphere Waveguide below and Shear Alfven waves upwards to the conjugate regions. The paper examines the scaling and limitations of the concept and suggests proof‐of‐principle experiments using the HAARP ionospheric heater.