Postsunset observations of ionospheric‐protonospheric coupling at Arecibo

Vickrey, J. F.; Swartz, Wesley E.; Farley, D. T.

doi:10.1029/ja084ia04p01310

Cited by 36 publications

(9 citation statements)

References 10 publications

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“…Park (1970) used whistler data near L = 4 to obtain rates of change of tube content he found upward fluxes in the day of about 5 x lOI rnp2 s-l and downward fluxes in the night of 3 x 1012 rnp2 s-l. Fluxes have also been reported from incoherent scatter radar data (Vickrey et al, 1979;Evans, 1975;Evans and Holt, 1978), but it is not meaningful to compare these results with ours (Saxton and Smith, 1989). Thus our results show a downward flux of ionization of the order of l-3 x 1012 me2 s-l which is in remarkable agreement with that of Saxton and Smith (1989).…”

Section: Data Selection and Methods Of Analysismentioning

confidence: 72%

Whistler observations of the quiet time plasmasphere-ionosphere coupling fluxes at low latitude

Lalmani¹,

Singh

Ahmad³

1996

Earth Moon Planet

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Observations of whistlers during quiet times made at low-latitude ground station Nainital (geomag. lat. 19" 1' N) are used to deduce plasmasphero-ionosphere coupling fluxes. The whistler data from 3 magnetically quiet days are presented that show a smooth decrease in dispersion with time. This decrease in dispersion is interpreted in terms of a corresponding decrease in electron content of tubes of ionization. The electron densities, electron tube contents (1016 el/m2-tube) and coupling fluxes (10 el m-l sT2) are computed by means of an accurate curve fittingmcthod developed by Tarcsai (1975) and are in good agreement with the results reported by other workers.

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Section: Data Selection and Methods Of Analysismentioning

confidence: 72%

Whistler observations of the quiet time plasmasphere-ionosphere coupling fluxes at low latitude

Lalmani¹,

Singh

Ahmad³

1996

Earth Moon Planet

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“…where the electron or ion number density N, the ionization production rate q, the attachment-type chemical reaction loss coefficient/3, and the plasma velocity ¾ are all height dependent. The solar radiation-generated ionization production is absent at night, but there is a downward protonospheric flux from above the level of 600-700 km, and this may be a nonnegligible source of ionization in the topside, especially in the early part of the night [Rao, 1968;Vickery et al, 1979]. However, we neglect this source term q for the purpose of the present study.…”

Section: The Methods Consists Of Calculating the Vertical Ionization Dmentioning

confidence: 99%

A MU radar‐based study of mid‐latitude F region response to a geomagnetic disturbance

Reddy¹,

Fukao²,

Takami³

et al. 1990

J. Geophys. Res.

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During the night of January 20–21, 1989, ionospheric incoherent scatter power measurements were made with the MU (middle and upper atmosphere) radar at Shigaraki (geographic latitude 34.85°N, longitude 136.10°E; geomagnetic latitude 24.9°, longitude 204.3°), Japan, and the electron density profiles in the 180‐ to 1000‐km height range were derived at 8‐min intervals. The observations showed the presence of three F region disturbances during the night. During the very large first disturbance, which lasted from 2300 to 0240 LT approximately, the height of maximum electron density Nm increased by 220 km in 2 hours to reach an altitude of 600 km. The other two, smaller disturbances occurred during 0300–0500 LT and 0530–0700 LT approximately. A detailed interpretation of the above F region disturbances is given. Examination of some high‐ and middle‐latitude magnetograms showed the beginning of an intense geomagnetic substorm at auroral latitudes at the start of the first F region disturbance, and a less intense substorm around the starting time of the second F region disturbance. On the basis of this evidence, the first two F region disturbances are interpreted as the result of large vertical drifts of F region ionization due to the substorm‐generated east‐west electric fields appearing at mid‐latitudes. The patterns of h′F variations during this night at five ionospheric stations in Japan support the above interpretation. Additionally, during the second disturbance the possible presence of a wind perturbation due to the equatorward propagation of a wave disturbance, generated probably by the first major substorm, is indicated by the MU radar data and the ionosonde data. The third F region disturbance is attributed to a neutral wind perturbation associated with a gravity wave traveling equatorward, the wave being generated most plausibly by the Joule heating during the first major substorm. The brief, unusual distortions of the F layer shape, as revealed by MU radar observations, are also interpreted as the consequence of an unusually large convergence of ionization in the bottomside of the F layer due to the unusually large electric field and wind perturbations. Theoretical calculations are made using the MU radar data and F region continuity equation, and the east‐west electric field values during the disturbances are quantified. During the first major rise of the F layer during 2300–0115 LT the inferred eastward electric field in the ionosphere at Shigaraki is found to be as large as 6±1 mV/m; and after this disturbance a westward electric field and/or a poleward meridional wind is found to occur for some time. An eastward electric field of about 3.0 mV/m is found to occur during the second F region disturbance, along with a possible meridional wind perturbation. The large eastward electric field around local midnight is most unusual in both magnitude and direction, because the theoretical models of disturbance electric fields predict a strong westward electric field in this LT sector; this result has important impl...

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“…The L value at ionospheric heights for this station is around 1.4, but the plasma content of such a protonospheric flux tube when filled is unlikely to be sufficient to account for observed electron content enhancements that have approached 10 t7 m -2. In addition, the rapid growth of some increases over time scales of less than 2 hours would require fluxes an order of magnitude greater than those observed at Arecibo [Vickrey et al, 1979]. Thus while downward plasma diffusion aided by a westward electric field may be a contributory factor to nighttime increases, the emptying of the protonospheric flux tubes alone is unable to account for the observations.…”

Section: Discussionmentioning

confidence: 92%

Nighttime enhancements in total electron content near Arecibo and their association with VHF scintillations

Kersley¹,

Aarons²,

Klobuchar³

1980

J. Geophys. Res.

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From the analysis of 16 months of transionospheric propagation data taken near Arecibo it has been found that there are associations between nighttime enhancements and quasi‐periodic fluctuations in total electron content and the occurrence of amplitude scintillations. A postmidnight peak is found in the occurrence of electron content increases, maximum wave activity, and largest scintillation index, with some evidence to suggest a second premidnight peak in winter and reduced probability of the features being found at equinox. An analysis of the larger‐scale variations of the total content data for three stations has shown that the postsunset minimum in electron content propagates at high speed toward the northeast, while the premidnight minimum advances toward the south with the main postmidnight maximum having a northward component of motion. The results are discussed in terms of the known dynamical features of the ionosphere at Arecibo and in particular the effects of the neutral wind on the bottomside ionosphere. It appears that conditions conducive to the production of nighttime enhancements in total electron content may also allow the penetration of medium scale gravity waves through the lower thermosphere with an unstable breakdown process giving rise to the development of scintillation‐producing irregularities.

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Postsunset observations of ionospheric‐protonospheric coupling at Arecibo

Cited by 36 publications

References 10 publications

Whistler observations of the quiet time plasmasphere-ionosphere coupling fluxes at low latitude

Whistler observations of the quiet time plasmasphere-ionosphere coupling fluxes at low latitude

A MU radar‐based study of mid‐latitude F region response to a geomagnetic disturbance

Nighttime enhancements in total electron content near Arecibo and their association with VHF scintillations

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