Density profiles of sporadic E-layers containing two metal ion species

Nygrén, T.; Jalonen, L.; Huuskonen, A.; Turunen, T.

doi:10.1016/0021-9169(84)90028-x

Cited by 17 publications

(2 citation statements)

References 22 publications

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“…The layers form in the ionospheric E region at altitudes mainly between about 90 and 125 km. They are thought to be caused by a combination of wind shears in the mesosphere and lower thermosphere together with strong background winds and electric fields [Whitehead, 1970;Kato et al, 1972;Nygren et al, 1984bNygren et al, , 1984aWhitehead, 1989;Batista et al, 1991;Bristow and Watkins, 1991;Kirkwood and von Zahn, 1991]. The layers are composed mainly of metallic ions, which recombine slowly [e.g., Harper et al, 1975].…”

Section: Introductionmentioning

confidence: 99%

Sporadic E ionization layers observed with radar imaging and ionospheric modification

Hysell

Munk

McCarrick

2014

Geophysical Research Letters

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Sporadic E ionization layers have been observed in the daytime subauroral ionospheric E layer by a 30 MHz radar in Alaska. The radar detects coherent backscatter from meter-scale field-aligned plasma density irregularities. The irregularities were generated by ionospheric modification-by the emission of strong HF electromagnetic waves directly beneath the layers-making the layers visible to the radar. Aperture-synthesis methods are used to generate imagery of the layers from the radar data. The layers are patchy, with patches organized along fronts spaced by tens of kilometers and propagating slowly toward the southwest. Similar, naturally occurring layers are commonly observed at middle latitudes at night in the absence of ionospheric modification. That the patchy layers can be found at high magnetic latitudes during the day argues that they are most likely produced through the interaction of the ionospheric layer with neutral atmospheric waves and instabilities. Attenuation of the radar echoes when the HF emission frequency exceeded the third harmonic of the electron gyrofrequency was observed and is discussed.

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Section: Introductionmentioning

confidence: 99%

Sporadic E ionization layers observed with radar imaging and ionospheric modification

Hysell

Munk

McCarrick

2014

Geophysical Research Letters

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“…the density profile for Mg + and Fe + ions which results when there is a balance between the accumulation of ions and diffusive processes related to the electron and ion pressure gradients [Nygrén et al, 1984a]. Note that the layers readily form over altitudes ranging from 107 to 121 km, and wider ranges are obtained including neutral winds..…”

Section: Thin Ionization Layers In the Ionospherementioning

confidence: 99%

Cross-Field Current Instabilities in Thin Ionization Layers and the Enhanced Aurora

Okuda¹

2008

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Abstract. Nearly half of the time, auroral displays exhibit thin, bright layers known as "enhanced aurora." There is a substantial body of evidence that connects these displays with thin, dense, heavy ion layers in the E-region. Based on the spectral characteristics of the enhanced layers, it is believed that they result when wave-particle interaction heats ambient electrons to energies at or just above the 17 eV ionization energy of N 2 . While there are several possible instabilities that could produce suprathermal electrons in thin layers, there has been no clear theoretical investigation which examines in detail how wave instabilities in the thin ionization layers could develop and produce the suprathermal electrons. We examine instabilities which would occur in thin, dense, heavy ion layers using extensive analytical analysis combined with particle simulations. We analyze a cross field current instability that is found to be strongly unstable in the heavy ion layers. Electrostatic simulations show that substantial heating of the ambient electrons occurs with energization at or above the N 2 ionization energy.

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Mechanisms for vertical separation of ions in sporadic-E layers

Jones

1989

Journal of Atmospheric and Terrestrial Physics

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Density profiles of sporadic E-layers containing two metal ion species

Cited by 17 publications

References 22 publications

Sporadic E ionization layers observed with radar imaging and ionospheric modification

Sporadic E ionization layers observed with radar imaging and ionospheric modification

Cross-Field Current Instabilities in Thin Ionization Layers and the Enhanced Aurora

Mechanisms for vertical separation of ions in sporadic-E layers

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