Solar X-ray flares and ionospheric sudden phase anomalies relationship: A solar cycle phase dependence

dc.contributor.authorPacini A.A.
dc.contributor.authorRaulin J.-P.
dc.date.accessioned2024-03-13T01:42:02Z
dc.date.available2024-03-13T01:42:02Z
dc.date.issued2006
dc.description.abstractWe investigate the relation between sudden phase anomaly (SPA) amplitudes (Δφ) and solar X-ray flares importance and study if it has a solar activity cycle dependence. We find a very significant correlation between Δφ and the X-ray fluences, Fx (time-integrated photon fluxes) in the range 0.5-2 Å. Compared with earlier works, the improvements of the Δφ versus FX relation allow us to study separately solar events as a function of their occurrence in the solar activity cycle, and we find that the Δφ versus FX relation is different depending on the epoch within the solar cycle. In particular, a minimum X-ray fluence of 2.5 × 10-6 J m-2 is needed during solar activity minimum to trigger a SPA, while during solar maximum, 7.0 × 10-6 J m-2 is required. Similarly, a solar flare will producer SPA during solar minimum that is greater by ∼2.6° M m -1 than would a flare of the same size during solar maximum. These results confirm recent findings about the dependence with the solar activity of the ionospheric undisturbed D region sensitivity. A possible consequence would be the monitoring of the long-term solar irradiance, which maintains the D region, through measurements of VLF wave propagation properties. Copyright 2006 by the American Geophysical Union.
dc.description.issuenumber9
dc.description.volume111
dc.identifier.doi10.1029/2006JA011613
dc.identifier.issn2169-9402
dc.identifier.urihttps://dspace.mackenzie.br/handle/10899/37764
dc.relation.ispartofJournal of Geophysical Research: Space Physics
dc.rightsAcesso Restrito
dc.titleSolar X-ray flares and ionospheric sudden phase anomalies relationship: A solar cycle phase dependence
dc.typeArtigo
local.scopus.citations46
local.scopus.eid2-s2.0-33947541159
local.scopus.updated2024-05-01
local.scopus.urlhttps://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=33947541159&origin=inward
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