A model for conjugate coupling from ionospheric dynamos in the acoustic frequency range

Jacobson, A. R.

doi:10.1029/ja091ia04p04404

Cited by 11 publications

(3 citation statements)

References 31 publications

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“…Moreover, for the SSH source, the reflection coefficient at the conjugate ionosphere appears to be small enough to allow fairly efficient coupling and quick relaxation to a steady state. These conditions are dependent on seasonal and solar conditions and will not always be met, suggesting the need for an electrodynamic treatment especially for longer transits or shorter periods [ Jacobson , ].…”

Section: Discussionmentioning

confidence: 99%

Ionospheric signatures of acoustic waves generated by transient tropospheric forcing

Zettergren

Snively

2013

Geophysical Research Letters

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[1] Acoustic waves generated by tropospheric sources may attain significant amplitudes in the thermosphere and overlying ionosphere. Although they are weak precursors to gravity waves in the mesosphere below, acoustic waves may achieve temperature and vertical wind perturbations on the order of approximately tens of Kelvin and m/s throughout the E and F regions. Their perturbations to total electron content are predicted to be detectable by groundbased radar and GPS receivers; they also drive field-aligned currents that may be detectable in situ via magnetometers. Although transient and short lived, ionospheric signatures of acoustic waves may provide new and quantitative insight into the forcing of the upper atmosphere from below.Citation: Zettergren, M. D., and J. B. Snively (2013), Ionospheric signatures of acoustic waves generated by transient tropospheric forcing, Geophys. Res. Lett., 40,[5345][5346][5347][5348][5349]

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Section: Discussionmentioning

confidence: 99%

Ionospheric signatures of acoustic waves generated by transient tropospheric forcing

Zettergren

Snively

2013

Geophysical Research Letters

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“…The neutral wave generates by collisions a local dynamo current in the E region which could produce mangetohydrodynamic waves. Jacobson [1986] has proposed a model for estimating the disturbance generated in the geomagnetically quiet, plasmasphere by short-period acoustic waves. He showed that geomagnetic micropulsations of extremely fine scale could be generated by explosive sources and studied by HF Doppler sounding.…”

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confidence: 99%

Nonlinear wave fronts and ionospheric irregularities observed by HF sounding over a powerful acoustic source

Blanc¹,

Rickel²

1989

Radio Science

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Different wave fronts affected by significant nonlinearities have been observed in the ionosphere by a pulsed HF sounding experiment at a distance of 38 km from the source point of a 4800-kg ammonium nitrate and fuel oil (ANFO) explosion on the ground. These wave fronts are revealed by partial reflections of the radio sounding waves. A small-scale irregular structure has been generated by a first wave front at the level of a sporadic E layer which characterized the ionosphere at the time of the experiment. The time scale of these fluctuations is about 1 to 2 s; its lifetime is about 2 min. Similar irregularities were also observed at the level of a second wave front in the F region. This structure appears also as diffusion on a continuous wave sounding at horizontal distances of the order of 200 km from the source. In contrast, a third front unaffected by irregularities may originate from the lowest layers of the ionosphere or from a supersonic wave front propagating at the base of the thermosphere. The origin of these structures is discussed. INTRODUCTION Acoustic waves are not the largest portion of ionospheric traveling waves as compared with gravity waves. They are most often associated with artificial sources (i.e., explosions or rockets) or with certain natural sources such as volcanic eruptions or earthquakes. In fact, they are present at the source of most disturbances that affect the Earth's environment and are also generated by meteorological storms [Georges, 1973] and auroral disturbances [Liska, 1977]. Blanc [1985] presented a summary of the effects of the acoustic waves in the upper atmosphere. During their vertical propagation the acoustic waves are amplified by the decrease of the atmospheric density and are often affected by shocks and nonlinearities. Theoretical studies predict that these nonlinearities cause rays to focus at the base of the thermosphere [Berther, 1968], which could be the origin of long-distance guided waves [Broche, 1977]. Such focalization may also cause neutral turbulences. uyn•.so in ionized plasma induce disturbances which affect the upper ionized Paper number 89RS• 181. •8-6604/89/89 RS-• 181 $08.• layers and the magnetosphere [Jacobson, 1986]. Alfven waves have been detected above a 250-T (1 T = 1000 kg) explosion [Galperin et al., 1985]. VLF emissions have also been observed by satellite during high-magnitude earthquakes several minutes after the earthquakes and may have a similar origin [Parrot and Lefeuvre, 1985]. Powerful explosions provide a good opportunity to investigate the complex mechanisms governing interaction of waves with the ionosphere, since the source is simple and well known. The 4.8-kT ammonium nitrate and fuel oil (ANFO) Minor Scale explosion detonated in New Mexico on June 27, 1985 at 1820:00 UT was the most powerful artificial acoustic source since nuclear explosions were halted. A large number of ionospheric measurements were made on this occasion [Fitzgerald, 1986; Jacobson et al., 1986]; this paper presents the results of an experiment conducted b...

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“…(12) it follows that the ®eld-aligned current j z can be excited either by an acoustical wave (for which r Â v n z 0 and r Á v n T 0) due to Hall conductivity, or by a non-compressional gravity wave (for which r Â v n z T 0 and r Á v n 0) due to Pedersen conductivity. The polarization of horizontally strati®ed p -region plasma and perturbations of plasma density induced by acoustic and gravity waves were also studied in electrostatic approximation by Jacobson (1986), and Jacobson and Bernhardt (1985), who demonstrated that at low latitudes electrostatic eects should be mirrored in the conjugated ionosphere.…”

Section: Magnetospheric and Ground Eects Of Magnetic Disturbances Indmentioning

confidence: 99%

Strong atmospheric disturbances as a possible origin of inner zone particle diffusion

Pokhotelov

Пилипенко

Parrot³

1999

Ann Geophysicae

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Abstract.A new mechanism of the atmosphere-magnetosphere interaction, which might be called``acousticmagnetospheric cyclotron accelerator'', is proposed. The idea of this mechanism stems from the fact that strong acoustical perturbations in the ionosphere (e.g., due to earthquakes, thunderstorms, etc.) may generate magnetic disturbances in the magnetosphere. Then, the latter will induce local resonant acceleration and subsequent inward diusion of trapped particles. This idea may be fruitful in the interpretation of some occasional increases in inner zone particle¯uxes which do not correlate with the solar or magnetospheric activities.

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A model for conjugate coupling from ionospheric dynamos in the acoustic frequency range

Cited by 11 publications

References 31 publications

Ionospheric signatures of acoustic waves generated by transient tropospheric forcing

Ionospheric signatures of acoustic waves generated by transient tropospheric forcing

Nonlinear wave fronts and ionospheric irregularities observed by HF sounding over a powerful acoustic source

Strong atmospheric disturbances as a possible origin of inner zone particle diffusion

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