A study of solar activity associated with polar-cap absorption

Warwick, Constance S.; Haurwitz, Marion W.

doi:10.1029/jz067i004p01317

Cited by 39 publications

(8 citation statements)

References 13 publications

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“…Reid and Leinbach [1959] and others have shown evidence to suggest the association of PCA events with optical and radio flares predominantly on the sun's Western hemisphere. Warwick and Haurwitz [1962] find the evidence in favor of such a West-East asymmetry inconclusive, but show that a more striking asymmetry is the excess ofPCA events in the Northern summer over the Northern winter. Subsequent studies do not appear to have fully resolved this point.…”

Section: Ionospheric Current Systemsmentioning

confidence: 79%

Influence of Solar Protons on High‐Latitude Ionospheric Disturbance

Elkins

1966

Radio Science

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High‐latitude ionospheric absorption is shown to exhibit a magnetic, rather than local, time dependence. The spatial and temporal variations of absorption are compared to the same variations of impact zones for solar protons in the energy range 50 MeV to 1.0 GeV, and the agreement is shown to be good. Similar agreement is found when various other ionospheric disturbance parameters are considered. The conclusion is tentatively reached that a more or less continuous flux of solar protons is entering the earth's atmosphere, which if valid, would have important consequences in the study of the energy balance of the ionosphere as well as that of the sun itself.

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Section: Ionospheric Current Systemsmentioning

confidence: 79%

Influence of Solar Protons on High‐Latitude Ionospheric Disturbance

Elkins

1966

Radio Science

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“…The PCA events listed in Appendix B were derived from measurements of radio-wave absorption in the northern polar cap (Jelly and Collins 1962). The resulting PCA-flare list differs substantially, for instance, from the list of Warwick and Haurwitz (1962). The tendency for PCA-associated flares to occur perferentially in the western hemisphere was noted by Reid and Leinbach (1959) and others, as soon as a sufficient number of such flares had been identified.…”

Section: T H E Influence O F Flare Locationmentioning

confidence: 89%

Criteria for the Association of Solar Flares With Geomagnetic Disturbances

Jenkins¹,

Paghis²

1963

Can. J. Phys.

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The statistical relation between solar flares of importance >2+ and the onset of geomagnetic disturbances was studied for 1949-01. Disturbances were defined as an increase in a, > 50, occurring within 13 hours or less, and these disturbances include both gradual and sudden commencement events. Associated radio noise bursts a t frequencies below 300 Mc were used to select 340 major-burst flares, and the effects of flare importance, time of solar epoch, and associated polar-capabsorption (PCA) events were considered in turn. A detailed examination was made of the effect of flare heliographic location. There is a strong positive correlation between the occurrence of major-burst flares and geomagnetic disturbances 1 to 3 days afterwards. The degree of correlation is approxi~nately doubled when the major-burst flare is associated with a PCA event. T h e most probable time delay between flares and disturbances is 1.5 to 2.0 days, and this ti~niug is relatively constant over a wide range of conditions.The dominance of northern storm-flares (Bell 1961) was confirmed for 1949-61. Detailed analysis shows that the effect is strongest for heliographic latitudes above 15" N. I n addition to this effect, there was a consistent western bias of the storm-flares in both the northern and southern hemispheres, for flares associated with either gradual or sudden commencement (SC) events, with maximum concentration occurring a t 10" W. to 15O W. Major-burst flares associated with PCA events also show this western bias; the data suggest that there is a systematic increase in east-west asymmetry in going from major-burst storm-flares to maior-burst PCA flares to PCA flares accomoanied bv mound-level cosmic-rav incieases. The corresponding longitudes of Inaximurn coicentration of the associated flares are about 10" -15" W., 45" W., and 75" W.

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“…Given the time of onset of a PCA event, we may want to determine the timing of a preceding solar-flare radio-burst event. In a recent paper Warwick and Haurwitz [1962] interval, and in three events there were significant gaps in the flare patrol data. These five events are not included in the following discussion.…”

Section: Dejence Research Telecommunications Establishmentmentioning

confidence: 97%

On the selection of solar-flare radio-burst events that are associated with polar-cap absorption

Paghis¹

1962

J. Geophys. Res.

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A study of solar activity associated with polar-cap absorption

Cited by 39 publications

References 13 publications

Influence of Solar Protons on High‐Latitude Ionospheric Disturbance

Influence of Solar Protons on High‐Latitude Ionospheric Disturbance

Criteria for the Association of Solar Flares With Geomagnetic Disturbances

On the selection of solar-flare radio-burst events that are associated with polar-cap absorption

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