Mapping of the polar electrojet current down to ionospheric <i>D</i> region altitudes

Werner, Douglas H.; Ferraro, Anthony J.

doi:10.1029/rs025i006p01375

Cited by 3 publications

(1 citation statement)

References 18 publications

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“…This result is not unexpected given that the bulk of the current flows at an altitude of ∼90 to 130 km ( E region ionosphere) [ Kamide and Brekke , 1977] while ionospheric heating modulates the conductivity at ∼60 to 90 km altitude ( D region) [ Stubbe and Kopka , 1977; Budilin et al , 1977; Rietveld et al , 1983]. While the electric field that drives the electrojet maps down along field lines to the D region owing to the high parallel conductivity, large‐scale currents do not flow in the D region owing to the lower Hall and Pedersen conductivities [ Werner and Ferraro , 1990]. It is possible that the uncorrelated intervals represent times when the D and E regions are decoupled.…”

Section: Discussionmentioning

confidence: 99%

Relationship between electrojet current strength and ELF signal intensity in modulated heating experiments

2009

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[1] The High Frequency Active Auroral Research Program (HAARP) facility is used to generate waves in the extremely low frequency (ELF) range via modulated HF heating of the ionosphere. This HF heating modulates the electron temperature in the D region ionosphere and leads to modulated conductivity and a time-varying current which then radiates at the modulation frequency. We investigate the relationship between the intensity of the HAARP-generated ELF signal and the strength of the east-west component of the auroral electrojet as measured by a ground-based magnetometer. We find that under all magnetic conditions, HAARP can generate ELF radiation detectable 37 km away with 73% of tones having an amplitude exceeding 0.15 pT. While strong ELF amplitudes (>1.5 pT) were most common during an enhanced electrojet, a weak electrojet can also support equally high ELF amplitudes. The relative change in ELF amplitude per unit change in electrojet current strength is inversely proportional to the absolute current strength. We interpret the dynamic relationship between ELF amplitude and electrojet current strength in terms of the time-variable ionospheric parameters and HF heating efficiency.Citation: Jin, G., M. Spasojevic, and U. S. Inan (2009), Relationship between electrojet current strength and ELF signal intensity in modulated heating experiments,

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Section: Discussionmentioning

confidence: 99%

Relationship between electrojet current strength and ELF signal intensity in modulated heating experiments

2009

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A finite difference solution of the polar electrojet current mapping boundary value problem

Werner¹,

Ferraro²

1991

J. Geophys. Res.

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An investigation is made of how the polar electrojet currents and associated electric fields map down to the ground. The boundary value problem which characterizes the downward mapping of the electrojet current will be formulated using potential theory. The electrojet current is represented by a simple Cowling model in which the geomagnetic field is vertical. A numerical solution to the electrojet mapping boundary value problem is obtained via a finite difference technique. This model is employed to study the downward mapping of the polar electrojet current during intense magnetic storms occurring under sunspot maximum daytime conditions. Results of this analysis suggest that as the current maps down through the D region, from an electrojet source in the E region, it is being attenuated as well as rotated. The rotation, however, is not present at altitudes below the D region. A possible application of electrojet mapping theory to the interpretation of high-latitude ionospheric modification data taken during polar electrojet events is discussed. 2354, 1961b. Tomko, A. A., Nonlinear phenomena arising from radio wave heating of the lower ionosphere, Rep. PSU-IRL-SCI-470, 165 pp., Commun. and Space Sci. Lab., The Penn. State Univ., University Park, 1981. Van Bladel, J., Electromagnetic Fields, 556 pp., Hemisphere Publishing, New York, 1985.Volland, H., Mapping of the electric field of the Sq current into the lower atmosphere,

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Determination of D region electron densities from the ELF frequency stepping experiment

Li¹,

Ferraro²

1990

Radio Science

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This paper describes the use of the generation of extremely low frequency (ELF) from heating of the D region of the ionosphere at high latitudes to estimate the degree of electron density ionization of the D region. In particular, the heating facility near Fairbanks, Alaska, known as the high-power auroral simulation (HIPAS) facility was used in this work. The theory of electron density synthesis is described, results of actual data presented, and electron densities determined. A new future ionospheric measurement technique is discussed.

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Mapping of the polar electrojet current down to ionospheric D region altitudes

Cited by 3 publications

References 18 publications

Relationship between electrojet current strength and ELF signal intensity in modulated heating experiments

Relationship between electrojet current strength and ELF signal intensity in modulated heating experiments

A finite difference solution of the polar electrojet current mapping boundary value problem

Determination of D region electron densities from the ELF frequency stepping experiment

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