Bibliography

Relationship between large-scale ionospheric field-aligned currents and electron/ion precipitations: DMSP observations

In this study, we have derived field-aligned currents (FACs) from magnetometers onboard the Defense Meteorological Satellite Project (DMSP) satellites. The magnetic latitude versus

Xiong, Chao; Stolle, Claudia; Alken, Patrick; Rauberg, Jan;

Published by: Earth, Planets and Space      Published on:

YEAR: 2020     DOI: 10.1186/s40623-020-01286-z

Study of the Equatorial and Low-Latitude Electrodynamic and Ionospheric Disturbances During the 22\textendash23 June 2015 Geomagnetic Storm Using Ground-Based and Spaceborne Techniques

We use a set of ground-based instruments (Global Positioning System receivers, ionosondes, magnetometers) along with data of multiple satellite missions (Swarm, C/NOFS, DMSP, GUVI) to analyze the equatorial and low-latitude electrodynamic and ionospheric disturbances caused by the geomagnetic storm of 22\textendash23 June 2015, which is the second largest storm in the current solar cycle. Our results show that at the beginning of the storm, the equatorial electrojet (EEJ) and the equatorial zonal electric fields were largely impacted by the prompt penetration electric fields (PPEF). The PPEF were first directed eastward and caused significant ionospheric uplift and positive ionospheric storm on the dayside, and downward drift on the nightside. Furthermore, about 45\ min after the storm commencement, the interplanetary magnetic field (IMF) Bz component turned northward, leading to the EEJ changing sign to westward, and to overall decrease of the vertical total electron content (VTEC) and electron density on the dayside. At the end of the main phase of the storm, and with the second long-term IMF Bz southward turn, we observed several oscillations of the EEJ, which led us to conclude that at this stage of the storm, the disturbance dynamo effect was already in effect, competing with the PPEF and reducing it. Our analysis showed no significant upward or downward plasma motion during this period of time; however, the electron density and the VTEC drastically increased on the dayside (over the Asian region). We show that this second positive storm was largely influenced by the disturbed thermospheric conditions.

Astafyeva, E.; Zakharenkova, I.; Hozumi, K.; Alken, P.; isson, Co; Hairston, M.; Coley, W.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 03/2018

YEAR: 2018     DOI: 10.1002/jgra.v123.310.1002/2017JA024981

Study of the equatorial and low-latitude electrodynamic and ionospheric disturbances during the 22—23 June 2015 geomagnetic storm using ground-based and spaceborne techniques

We use a set of ground-based instruments (Global Positioning System receivers, ionosondes, magnetometers) along with data of multiple satellite missions (Swarm, C/NOFS, DMSP, GUVI) to analyze the equatorial and low-latitude electrodynamic and ionospheric disturbances caused by the geomagnetic storm of 22–23 June 2015, which is the second largest storm in the current solar cycle.

Astafyeva, E; Zakharenkova, I; Hozumi, K; Alken, P; isson, Co; Hairston, Marc; Coley, William;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2018     DOI: 10.1002/2017JA024981

Study of the equatorial and low-latitude electrodynamic and ionospheric disturbances during the 22—23 June 2015 geomagnetic storm using ground-based and spaceborne techniques

Astafyeva, E; Zakharenkova, I; Hozumi, K; Alken, P; isson, Co; Hairston, Marc; Coley, William;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2018     DOI:

Prompt penetration electric fields and the extreme topside ionospheric response to the June 22--23, 2015 geomagnetic storm as seen by the Swarm constellation

Using data from the three Swarm satellites, we study the ionospheric response to the intense geomagnetic storm of June 22\textendash23, 2015. With the minimum SYM-H excursion of -207 nT, this storm is so far the second strongest geomagnetic storm in the current 24th solar cycle. A specific configuration of the Swarm satellites allowed investigation of the evolution of the storm-time ionospheric alterations on the day- and the nightside quasi-simultaneously. With the development of the main phase of the storm, a significant dayside increase of the vertical total electron content (VTEC) and electron density Ne was first observed at low latitudes on the dayside. From\ ~22\ UT of 22 June to\ ~1\ UT of 23 June, the dayside experienced a strong negative ionospheric storm, while on the nightside an extreme enhancement of the topside VTEC occurred at mid-latitudes of the northern hemisphere. Our analysis of the equatorial electrojet variations obtained from the magnetic Swarm data indicates that the storm-time penetration electric fields were, most likely, the main driver of the observed ionospheric effects at the initial phase of the storm and at the beginning of the main phase. The dayside ionosphere first responded to the occurrence of the strong eastward equatorial electric fields. Further, penetration of westward electric fields led to gradual but strong decrease of the plasma density on the dayside in the topside ionosphere. At this stage, the disturbance dynamo could have contributed as well. On the nightside, the observed extreme enhancement of the Ne and VTEC in the northern hemisphere (i.e., the summer hemisphere) in the topside ionosphere was most likely due to the combination of the prompt penetration electric fields, disturbance dynamo and the storm-time thermospheric circulation. From\ ~2.8\ UT, the ionospheric measurements from the three Swarm satellites detected the beginning of the second positive storm on the dayside, which was not clearly associated with electrojet variations. We find that this second storm might be provoked by other drivers, such as an increase in the thermospheric composition.

Astafyeva, Elvira; Zakharenkova, Irina; Alken, Patrick;

Published by: Earth, Planets and Space      Published on: 09/2016

YEAR: 2016     DOI: 10.1186/s40623-016-0526-x