scholarly journals Ionospheric response to solar and interplanetary disturbances: a Swarm perspective

2019 ◽  
Vol 377 (2148) ◽  
pp. 20180098 ◽  
Author(s):  
G. Balasis ◽  
C. Papadimitriou ◽  
A. Z. Boutsi
Keyword(s):  
Solar Cycle ◽  
Electric Fields ◽  
Space Weather ◽  
Low Earth Orbit ◽  
Topside Ionosphere ◽  
Plasma Instabilities ◽  
Radio Communications ◽  
Weather Impact ◽  
Ionospheric Response ◽  
Solar Eruptions

The ionospheric response to solar and interplanetary disturbances has been the subject of intense study for several decades. For 5 years now, the European Space Agency's Swarm fleet of satellites surveys the Earth's topside ionosphere, measuring magnetic and electric fields at low-Earth orbit with unprecedented detail. Herein, we study in situ the ionospheric response in terms of the occurrence of plasma instabilities based on 2 years of Swarm observations. Plasma instabilities are an important element of space weather because they include irregularities like the equatorial spread F events, which are responsible for the disruption of radio communications. Moreover, we focus on three out of the four most intense geospace magnetic storms of solar cycle 24 that occurred in 2015, including the St Patrick's Day event, which is the strongest magnetic storm of the present solar cycle. We examine the associated ionospheric response at Swarm altitudes through the estimation of a Swarm Dst-like index. The newly proposed Swarm derived Dst index may be suitable for space weather applications. This article is part of the theme issue ‘Solar eruptions and their space weather impact’.

scholarly journals Predicting the geoeffective properties of coronal mass ejections: current status, open issues and path forward

2019 ◽  
Vol 377 (2148) ◽  
pp. 20180096 ◽  
Author(s):  
A. Vourlidas ◽  
S. Patsourakos ◽  
N. P. Savani
Keyword(s):  
Space Weather ◽  
Coronal Mass Ejections ◽  
Technology Development ◽  
Action Plan ◽  
Current Status ◽  
Weather Impact ◽  
Solar Eruptions ◽  
Holding Back ◽  
Open Issues ◽  
Made In

Much progress has been made in the study of coronal mass ejections (CMEs), the main drivers of terrestrial space weather thanks to the deployment of several missions in the last decade. The flow of energy required to power solar eruptions is beginning to be understood. The initiation of CMEs is routinely observed with cadences of tens of seconds with arc-second resolution. Their inner heliospheric evolution can now be imaged and followed routinely. Yet relatively little progress has been made in predicting the geoeffectiveness of a particular CME. Why is that? What are the issues holding back progress in medium-term forecasting of space weather? To answer these questions, we review, here, the measurements, status and open issues on the main CME geoeffective parameters; namely, their entrained magnetic field strength and configuration, their Earth arrival time and speed, and their mass (momentum). We offer strategies for improving the accuracy of the measurements and their forecasting in the near and mid-term future. To spark further discussion, we incorporate our suggestions into a top-level draft action plan that includes suggestions for sensor deployment, technology development and modelling/theory improvements. This article is part of the theme issue ‘Solar eruptions and their space weather impact’.

Space Weather Impact on High Latitude Ionospheric TEC During the End of Solar Cycle 23rd at Maitri, Antarctica

2012 ◽  
Vol 18 (1) ◽  
pp. 241-246
Author(s):  
Prakash Khatarkar ◽  
Purushottam Bhawre ◽  
Pravaiz A. Khan ◽  
Azad A. Mansoori ◽  
Shweta Mukherjee ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Space Weather ◽  
High Latitude ◽  
Weather Impact

scholarly journals Space weather impact on the equatorial and low latitude F-region ionosphere over India

2006 ◽  
Vol 24 (1) ◽  
pp. 97-105 ◽  
Author(s):  
R. S. Dabas ◽  
R. M. Das ◽  
V. K. Vohra ◽  
C. V. Devasia
Keyword(s):  
Magnetic Storm ◽  
Electric Fields ◽  
Space Weather ◽  
Recovery Phase ◽  
Equatorial Region ◽  
Storm Events ◽  
Low Latitude ◽  
Equatorial Station ◽  
Weather Impact ◽  
F Region

Abstract. For a detailed study of the space weather impact on the equatorial and low latitude F-region, the ionospheric response features are analysed during the periods of three recent and most severe magnetic storm events of the present solar cycle which occurred in October and November 2003, and November 2004. The F-layer base height (h'F), peak height (hmF2) and critical frequency (foF2) data, from Trivandrum, an equatorial station and Delhi, a low latitude location, are examined during the three magnetic storm periods. The results of the analysis clearly shows that the height of the F-region (both h'F and hmF2), at the equator and low latitude, simultaneously increases by 200 to 300 km, in association with maximum negative excursion of Dst values around the midnight hours with a large depletion of ionization over the equator, which is followed by an ionization enhancement at low latitude during the recovery phase of the storm. At Delhi, fast variations up to 200 m/s are also observed in the F-layer vertical upward/downward velocity, calculated using Doppler shifts, associated with the maximum negative excursion of Dst. This shows that during magnetic disturbances, the equatorial ionization anomaly (EIA) expands to a much wider latitude than the normal fountain driven by the E/F-layer dynamo electric fields. It is also observed that during the main phase of the storm, at low latitude there is generally an enhancement of F-region ionization with an increase in h'F/hmF2 but in the equatorial region, the ionization collapses with a decrease in h'F/hmF2, especially after sunset hours. In addition, at the equator the normal pre-sunset hours' enhancement in h'F is considerably suppressed during storm periods. This might be due to changes in magnitude and direction of the zonal electric field affecting the upward E×B drift and hence the plasma distribution in the form of a decrease in electron density in the equatorial region and an increase in the low latitude region. In association with disturbance electric fields, the enhanced storm-induced equatorward meridional winds in the thermosphere can also further amplify the F-layer height rise at low latitudes during the post-midnight hours, as observed in two of the storm periods.

scholarly journals Plasmasphere and Topside Ionosphere Reconstruction using METOP Satellite Data during Geomagnetic Storms

2020 ◽  
Author(s):  
Fabricio dos Santos Prol ◽  
Mainul Hoque ◽  
Arthur Amaral Ferreira
Keyword(s):  
Electron Density ◽  
Space Weather ◽  
Geomagnetic Storms ◽  
Tomographic Reconstruction ◽  
Satellite System ◽  
Low Earth Orbit ◽  
Topside Ionosphere ◽  
Reconstruction Technique ◽  
Electron Content ◽  
Total Electron

As part of the space weather monitoring, the response of the ionosphere and plasmasphere to geomagnetic storms is typically under continuous supervision by operational services. Fortunately, Global Navigation Satellite System (GNSS) receivers on board low Earth orbit satellites provides a unique opportunity for developing image representations that can capture the global distribution of the electron density in the plasmasphere and topside ionosphere. Among the difficulties of plasmaspheric imaging based on GNSS measurements, the development of procedures to invert the Total Electron Content (TEC) into electron density distributions remains as a challenging task. In this study, a new tomographic reconstruction technique is presented to estimate the electron density from TEC data along the METOP (Meteorological Operational) satellites. The proposed method is evaluated during four geomagnetic storms to check the capabilities of the tomography for space weather monitoring. The investigation shows that the developed method can successfully capture and reconstruct well-known enhancement and decrease of electron density variabilities during storms. The comparison with in-situ electron densities has shown an improvement around 11% and a better description of plasma variabilities due to the storms compared to the background. Our study also reveals that the plasmasphere TEC contribution to ground-based TEC may vary 10 to 60% during geomagnetic storms, and the contribution tends to reduce during the storm-recovery phase

scholarly journals Introduction to the physics of solar eruptions and their space weather impact

2019 ◽  
Vol 377 (2148) ◽  
pp. 20190152 ◽  
Author(s):  
Vasilis Archontis ◽  
Loukas Vlahos
Keyword(s):  
Space Weather ◽  
Large Scale ◽  
Interplanetary Space ◽  
Active Regions ◽  
Solar Interior ◽  
Physical Processes ◽  
Weather Impact ◽  
Solar Eruptions ◽  
Earth Connection ◽  
Magnetic Disturbances

The physical processes, which drive powerful solar eruptions, play an important role in our understanding of the Sun–Earth connection. In this Special Issue, we firstly discuss how magnetic fields emerge from the solar interior to the solar surface, to build up active regions, which commonly host large-scale coronal disturbances, such as coronal mass ejections (CMEs). Then, we discuss the physical processes associated with the driving and triggering of these eruptions, the propagation of the large-scale magnetic disturbances through interplanetary space and the interaction of CMEs with Earth's magnetic field. The acceleration mechanisms for the solar energetic particles related to explosive phenomena (e.g. flares and/or CMEs) in the solar corona are also discussed. The main aim of this Issue, therefore, is to encapsulate the present state-of-the-art in research related to the genesis of solar eruptions and their space-weather implications. This article is part of the theme issue ‘Solar eruptions and their space weather impact’.

scholarly journals From solar sneezing to killer electrons: outer radiation belt response to solar eruptions

2019 ◽  
Vol 377 (2148) ◽  
pp. 20180097 ◽  
Author(s):  
Ioannis A. Daglis ◽  
Christos Katsavrias ◽  
Marina Georgiou
Keyword(s):  
Electric Fields ◽  
Space Weather ◽  
High Speed ◽  
Radiation Belt ◽  
Interplanetary Space ◽  
Plasma Waves ◽  
Potential Hazard ◽  
Interplanetary Coronal Mass Ejections ◽  
Outer Radiation Belt ◽  
Solar Eruptions

Electrons in the outer Van Allen (radiation) belt occasionally reach relativistic energies, turning them into a potential hazard for spacecraft operating in geospace. Such electrons have secured the reputation of satellite killers and play a prominent role in space weather. The flux of these electrons can vary over time scales of years (related to the solar cycle) to minutes (related to sudden storm commencements). Electric fields and plasma waves are the main factors regulating the electron transport, acceleration and loss. Both the fields and the plasma waves are driven directly or indirectly by disturbances originating in the Sun, propagating through interplanetary space and impacting the Earth. This paper reviews our current understanding of the response of outer Van Allen belt electrons to solar eruptions and their interplanetary extensions, i.e. interplanetary coronal mass ejections and high-speed solar wind streams and the associated stream interaction regions.This article is part of the theme issue ‘Solar eruptions and their space weather impact’.

Solar cycle effects on the electric fields in the equatorial ionosphere

1977 ◽  
Vol 82 (32) ◽  
pp. 5257-5261 ◽  
Author(s):  
R. F. Woodman ◽  
R. G. Rastogi ◽  
C. Calderon
Keyword(s):  
Solar Cycle ◽  
Electric Fields ◽  
Equatorial Ionosphere

scholarly journals Topside Ionosphere and Plasmasphere Modelling Using GNSS Radio Occultation and POD Data

2021 ◽  
Vol 13 (8) ◽  
pp. 1559
Author(s):  
Fabricio S. Prol ◽  
M. Mainul Hoque
Keyword(s):  
Solar Activity ◽  
Electron Density ◽  
Radio Occultation ◽  
Geomagnetic Latitude ◽  
Low Earth Orbit ◽  
Activity Level ◽  
Topside Ionosphere ◽  
Electron Content ◽  
Total Electron ◽  
Solar Activity Level

A 3D-model approach has been developed to describe the electron density of the topside ionosphere and plasmasphere based on Global Navigation Satellite System (GNSS) measurements onboard low Earth orbit satellites. Electron density profiles derived from ionospheric Radio Occultation (RO) data are extrapolated to the upper ionosphere and plasmasphere based on a linear Vary-Chap function and Total Electron Content (TEC) measurements. A final update is then obtained by applying tomographic algorithms to the slant TEC measurements. Since the background specification is created with RO data, the proposed approach does not require using any external ionospheric/plasmaspheric model to adapt to the most recent data distributions. We assessed the model accuracy in 2013 and 2018 using independent TEC data, in situ electron density measurements, and ionosondes. A systematic better specification was obtained in comparison to NeQuick, with improvements around 15% in terms of electron density at 800 km, 26% at the top-most region (above 10,000 km) and 26% to 55% in terms of TEC, depending on the solar activity level. Our investigation shows that the developed model follows a known variation of electron density with respect to geographic/geomagnetic latitude, altitude, solar activity level, season, and local time, revealing the approach as a practical and useful tool for describing topside ionosphere and plasmasphere using satellite-based GNSS data.

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