On the Observation of Ionospheric Effects due to Dumping of Trapped Particles

Gassmann, G. J.; Pike, C. P.

doi:10.1007/978-94-010-3553-8_28

Cited by 4 publications

(1 citation statement)

References 2 publications

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“…Recent work by Imhof and Smith (1965) and Williams and Kohl (1965) shows that the electron population on low L shells is much smaller east of the South Atlantic anomaly than west of it. An assessment of the significance that the magnetic anomalies and their conjugate regions would have on longitudinally drifting electrons has been given by Gassmann and Pike (1966). Their conclusion was that the western slopes of the magnetic anomalies may feed sizable amounts of energy into the ionosphere by precipitation of electrons and that the conjugate region must be affected too .…”

Section: Introductionmentioning

confidence: 99%

Conjugate F‐Region Enhancement Related to the South Atlantic Magnetic Anomaly

1968

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Airborne ionospheric measurements have .been made during solar minimum years (1963)(1964)(1965) off the east coast of the United States from Boston to Puerto Rico, the area conjugate to the western slope of the South Atlantic magnetic anomaly. Vertical incidence ionosonde soundings were made on 17 flights under both day and night conditions, and were compared with ground-based observations along the 75• W meridian. On several late afternoon and night flights, higher values of foF2 were observed over the North Atlantic Ocean compared with the same local time values observed by the ground stations. During the daytime, no such enhancements were found. To determine the eastwest extent of this anomaly, an additional analysis was made using published true-height profile data (from White Sands, New Mexico, as well as from the east coast chain), which revealed that the east coast exhibits a significant enhancement of F-region ionization when compared to White Sands and manifests seasonal and diurnal variations. Earlier reported measurements in the southern conjugate region indicated that there is an effect of dumping of trapped electrons, which is most pronounced in the F layer on the western slope of the magnetic anomaly between L = 1. 75 and 3 during December and January. No significant D-orE-region effects have been observed in both hemispheres as yet. Circumstantial evidence indicates that there are F-region ionospheric effects in the Northern Hemisphere due to energetic electrons backscattered from the southern dumping region. . IntroductionProduction of ionization by particles is well accepted for the ·ionosphere in the auroral zones and for all the lower D layer. While the rest of the ionosphere was thought to be ·produced solely by electromagnetic radiation, evidence, as accumulated in recent years, indicates that this might not be true. The arctic IGY data for example, as analyzed by Knecht (1959), Duncan (1962), andPenndorf (1965) require the assumption of an ionizing agent other than light. For an explanation of the "winterspur" anomaly in the F2 region, Thomas (1963) postulated precipitation of particles. The absence of the latter was also postulated for a possible explanation of the trough of foF2 near L = 3.5 during late aftemoon and night, reported by Muldrew (1965).We deal here with one of the various possible types of particle precipitation, namely dumping of trapped electrons · due to their longitudinal drift. . We specifically consider the evidence of this in the area conjugate to the South Atlantic magnetic anomaly.Satellite measurements of magnetospheric particles trapped in the earth's magnetic field have revealed that there are significant loss processes governing the particle population. loss process is scattering or absorption of these particles in the upper atmosphere, so one should expect observable ionization effects in the ionosphere. ·nessler (1959) suggested that this loss should be larger in regions where the earth's magnetic field strength is anomalously low, thus allowing the longitudin...

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Section: Introductionmentioning

confidence: 99%

Conjugate F‐Region Enhancement Related to the South Atlantic Magnetic Anomaly

1968

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Airglow observations from OSO-B2 satellite

Sparrow¹,

Ney²,

Burnett³

et al. 1968

J. Geophys. Res.

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Four photometers sensitive to three wide spectral bands observed the continuum airglow in profile once per orbit from the satellite OSO-B2. The tangential enhancement (factor of 35) gave good discrimination against zodiacal light and background starlight. Airglow intensity in the astronomical visible spectral region varied between 0.1 and 0.9 R/A and from 0.06 to 0.5 R/A in the blue spectral region. No significant latitude variation was found although a considerable temporal change occurred during the ten months of satellite operation. No correlation was found between airglow intensity and the South Atlantic geomagnetic anomaly or with solar events.

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Modeling the ion chemistry of the D region: A case study based upon the 1966 total solar eclipse

Sears¹,

Heaps²,

Niles³

1981

J. Geophys. Res.

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The November 12, 1966, solar eclipse has been modeled by a large multispecies chemistry code and the results compared with the numerous experimental measurements that were made at that time. Measured preeclipse values of electron density and code‐predicted values agree closely if ionization by precipitating electrons from the radiation belts is included. Current gas‐phase ion chemistry does not predict the rapid decrease and subsequent reconstitution of electron density about totality in the 65‐ to 85‐km region, nor does it produce the large number of negative ions above 70 km that can be inferred from the experimental data. While basic constraints can be placed on the electron attachment processes because of the experimental data, an entirely new class of physical processes may need to be included to explain this phase of D region behavior.

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On the Observation of Ionospheric Effects due to Dumping of Trapped Particles

Cited by 4 publications

References 2 publications

Conjugate F‐Region Enhancement Related to the South Atlantic Magnetic Anomaly

Conjugate F‐Region Enhancement Related to the South Atlantic Magnetic Anomaly

Airglow observations from OSO-B2 satellite

Modeling the ion chemistry of the D region: A case study based upon the 1966 total solar eclipse

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