Bibliography

High and mid latitude and near subsolar point ionospheric and thermospheric responses to the solar flares and geomagnetic storms during low solar activity periods of 2017 and 2020

The paper observes the super-imposed effects of intense and moderate solar flares and Coronal Mass Ejection (CME) and High Speed Solar Wind (HSSW) driven geomagnetic storm events on the ionosphere and thermosphere at mid and high latitudes during low solar activity periods. The observations are conducted over a fixed longitude (∼117°W geographic) during May 27–31, 2017 (duration with intense geomagnetic storm without any significant solar flare event), September 3–6, 2017 (duration with solar flare events), September 7–16, 2017 (duration with intense to moderate solar flares as well as geomagnetic storms) and November 28–30, 2020 (duration with a moderate solar flare event with no geomagnetic storm in association). It is found that the effects were the highest during May 27–31, 2017 among all of these events. From the observations of super-imposed effects of the geophysical events, it was found that the effects of an X-class solar flare on September 10–12, 2017 on mid-latitude ionization were suppressed by the Disturbed Dynamo Electric Field (DDEF) from high latitudes during the recovery phase of an intense CME driven geomagnetic storm. The weak effects were also explained by the position of origination of the flare at the Sun. Correlations were observed between the variations in O/N2, neutral wind velocities and the mid and high latitude Total Electron Content (TEC) during these periods. Possible explanation is given for those few cases (for example, September 14, 2017) when the variations in O/N2 mismatched with the local TEC especially in the mid-latitudes. The effects of the solar flare event on November 28–30, 2020 which were short-lived have also been also observed at locations near the subsolar point from low latitudes in the southern hemisphere.

Sur, Dibyendu; Ray, Sarbani; Paul, Ashik;

Published by: Advances in Space Research      Published on: jul

YEAR: 2022     DOI: 10.1016/j.asr.2022.04.024

CME driven storms; HSSW driven storms; Joule heating; O/N ratio; Plasmaspheric contributions; Solar flare

Impact of CME and HSSW driven geomagnetic storms on thermosphere and ionosphere as observed from mid-latitudes

The present paper reports magnetospheric-thermospheric-ionospheric interactions, observed during geomagnetically disturbed periods in 2015–2016 from mid-latitude stations located in the US-Pacific longitudes (\textasciitilde120°W geographic). These interactions have been analyzed for a series of Coronal Mass Ejection (CME) and High Speed Solar Wind (HSSW) driven geomagnetic storms during the moderate solar activity periods. The geomagnetically disturbed periods under consideration in this paper have an interesting feature of the occurrences of one or more HSSW events following an intense CME driven intense geomagnetic storm. Correlations were observed between the solar and geomagnetic parameters, hemispherically integrated Joule heating, changes in O/N2 ratio, corresponding changes in neutral wind velocities and mid-latitude Vertical Total Electron Content (VTEC) in most of the cases. Prolonged effects of neutral wind driven equatorward plasma transport process were noticed during the period of the summer solstice (June 23–26, 2015) which was correlated with the hemispherically integrated Joule heating and ionospheric conductivities. The effects of storm onset were observed during March 17–18, 2015. The influences of the ‘super-fountain effect’ in terms of Prompt Penetration Electric Field (PPEF) were seen during the main phases of the geomagnetic storms from these mid-latitude stations. This is correlated with the strength of Equatorial Electrojet (EEJ).

Sur, Dibyendu; Ray, Sarbani; Paul, Ashik;

Published by: Advances in Space Research      Published on: aug

YEAR: 2021     DOI: 10.1016/j.asr.2021.03.027

CME and HSSW storms; Joule heating; Meridional and zonal wind; O/N ratio; Plasma transport; VTEC