scholarly journals Outer radiation belt dropout dynamics following the arrival of two interplanetary coronal mass ejections

2016 ◽  
Vol 43 (3) ◽  
pp. 978-987 ◽  
Author(s):  
L. R. Alves ◽  
L. A. Da Silva ◽  
V. M. Souza ◽  
D. G. Sibeck ◽  
P. R. Jauer ◽  
...  
Keyword(s):  
Coronal Mass Ejections ◽  
Radiation Belt ◽  
Interplanetary Coronal Mass Ejections ◽  
Outer Radiation Belt

scholarly journals Outer Van Allen Radiation Belt Response to Interacting Interplanetary Coronal Mass Ejections

2019 ◽  
Vol 124 (3) ◽  
pp. 1927-1947 ◽  
Author(s):  
E. K. J. Kilpua ◽  
D. L. Turner ◽  
A. N. Jaynes ◽  
H. Hietala ◽  
H. E. J. Koskinen ◽  
...  
Keyword(s):  
Coronal Mass Ejections ◽  
Radiation Belt ◽  
Interplanetary Coronal Mass Ejections

scholarly journals Outer Van Allen belt trapped and precipitating electron flux responses to two interplanetary magnetic clouds of opposite polarity

2020 ◽  
Vol 38 (4) ◽  
pp. 931-951
Author(s):  
Harriet George ◽  
Emilia Kilpua ◽  
Adnane Osmane ◽  
Timo Asikainen ◽  
Milla M. H. Kalliokoski ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Radiation Belt ◽  
Magnetic Cloud ◽  
Opposite Polarity ◽  
Initial Energy ◽  
Magnetic Clouds ◽  
Interplanetary Coronal Mass Ejections ◽  
Field Orientation ◽  
Outer Radiation Belt ◽  
Trapped Electron

Abstract. Recently, it has been established that interplanetary coronal mass ejections (ICMEs) can dramatically affect both trapped electron fluxes in the outer radiation belt and precipitating electron fluxes lost from the belt into the atmosphere. Precipitating electron fluxes and energies can vary over a range of timescales during these events. These variations depend on the initial energy and location of the electron population and the ICME characteristics and structures. One important factor controlling electron dynamics is the magnetic field orientation within the ejecta that is an integral part of the ICME. In this study, we examine Van Allen Probes (RBSPs) and Polar Orbiting Environmental Satellites (POESs) data to explore trapped and precipitating electron fluxes during two ICMEs. The ejecta in the selected ICMEs have magnetic cloud characteristics that exhibit the opposite sense of the rotation of the north–south magnetic field component (BZ). RBSP data are used to study trapped electron fluxes in situ, while POES data are used for electron fluxes precipitating into the upper atmosphere. The trapped and precipitating electron fluxes are qualitatively analysed to understand their variation in relation to each other and to the magnetic cloud rotation during these events. Inner magnetospheric wave activity was also estimated using RBSP and Geostationary Operational Environmental Satellite (GOES) data. In each event, the largest changes in the location and magnitude of both the trapped and precipitating electron fluxes occurred during the southward portion of the magnetic cloud. Significant changes also occurred during the end of the sheath and at the sheath–ejecta boundary for the cloud with south to north magnetic field rotation, while the ICME with north to south rotation had significant changes at the end boundary of the cloud. The sense of rotation of BZ and its profile also clearly affects the coherence of the trapped and/or precipitating flux changes, timing of variations with respect to the ICME structures, and flux magnitude of different electron populations. The differing electron responses could therefore imply partly different dominant acceleration mechanisms acting on the outer radiation belt electron populations as a result of opposite magnetic cloud rotation.

Electron Flux and Precipitation During ICME Case Studies

2020 ◽  
Author(s):  
Harriet E. George ◽  
Emilia Kilpua ◽  
Adnane Osmane ◽  
Timo Asikainen ◽  
Craig J. Rodger ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Radiation Belt ◽  
Electron Flux ◽  
Rotating Magnetic Field ◽  
Upper Atmosphere ◽  
Interplanetary Coronal Mass Ejections ◽  
Outer Radiation Belt ◽  
Magnetic Flux Ropes ◽  
Flux Ropes ◽  
Flux Response

<p>Interplanetary coronal mass ejections (ICMEs) can dramatically affect electrons in the outer radiation belt. Electron energy flux and location varies over a range of timescales during these events, depending on ICME characteristics. This highly complex response means that electron flux within the outer radiation belt and precipitation into the upper atmosphere during ICMEs is not yet fully understood. This study analyses the electron response to two ICMEs, which occurred near the maximum of Solar Cycle 24. Both ICMEs had leading shocks and sheaths, followed by magnetic flux ropes in the ejecta. The magnetic field in these flux ropes rotated throughout the events, with opposite rotation in each event. The field rotated from south to north during the first event, while the second event had rotation from north to south. Data from Van Allen Probes were used to study electron flux variation in the outer radiation belt, while POES data were used for electron precipitation into the upper atmosphere. Qualitative analysis of these data was carried out in order to characterise the temporal and spatial variations in electron flux and precipitation throughout these two events, with particular focus on the effects of the sheath and rotating magnetic field in the ICME ejecta. In both events, we observe enhanced precipitation at mid-latitudes during the southward portion of the ejecta, with greater enhancements taking place in lower energy electron populations. By contrast, flux of outer radiation belt electron populations differs significantly between the two ICMEs, highlighting the complexity of the electron flux response to these space weather events.</p>

scholarly journals Outer Van Allen belt trapped and precipitating electron flux responses to two interplanetary magnetic clouds of opposite polarity

2020 ◽  
Author(s):  
Harriet George ◽  
Emilia Kilpua ◽  
Adnane Osmane ◽  
Timo Asikainen ◽  
Milla M. H. Kalliokoski ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Radiation Belt ◽  
Electron Flux ◽  
Magnetic Cloud ◽  
Opposite Polarity ◽  
Magnetic Clouds ◽  
Interplanetary Coronal Mass Ejections ◽  
Field Orientation ◽  
Outer Radiation Belt ◽  
Trapped Electron

Abstract. Recently, it has been established that interplanetary coronal mass ejections (ICMEs) can dramatically affect both trapped electron fluxes in the outer radiation belt and precipitating electron fluxes lost from the belt into the atmosphere. Precipitating electron flux and energy can vary over a range of timescales during these events. These variations depend on the initial energy and location of the electron population, as well as the ICME characteristics and structures. One important factor controlling electron dynamics is the magnetic field orientation within the ejecta that is an integral part of the ICME. In this study, we examine Van Allen Probes (RBSP) and Polar Orbiting Environmental Satellites (POES) data to explore trapped and precipitating electron fluxes during two ICMEs. The ejecta in the selected ICMEs have magnetic cloud characteristics that exhibit opposite sense of rotation of the north-south magnetic field component (BZ). RBSP data are used to study trapped electron fluxes in situ, while POES data are used for electron fluxes precipitating into the upper atmosphere. The trapped and precipitating electron fluxes are qualitatively analysed to understand their variation in relation to each other and to magnetic cloud rotation during these events. Inner magnetospheric wave activity was also estimated using RBSP and Geostationary Operational Environmental Satellite (GOES) data. In each event, the largest changes in the location and magnitude of both the trapped and precipitating electron fluxes occurred during the southward portion of the magnetic cloud. Significant changes also occurred during the end of the sheath and at the sheath-cloud boundary for the cloud with south to north magnetic field rotation, while the ICME with north to south rotation had significant changes at the end boundary of the cloud. The sense of rotation of BZ and its profile also clearly affects the coherence of the trapped/precipitating flux changes, timing of variations with respect to the ICME structures, and flux magnitude of different electron populations. The differing electron responses could therefore imply partly different dominant acceleration mechanisms acting on the outer radiation belt electron populations as a result of opposite magnetic cloud rotation.

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’.

scholarly journals Outer radiation belt and inner magnetospheric response to sheath regions of coronal mass ejections: A statistical analysis

2019 ◽  
Author(s):  
Milla M. H. Kalliokoski ◽  
Emilia K. J. Kilpua ◽  
Adnane Osmane ◽  
Drew L. Turner ◽  
Allison N. Jaynes ◽  
...  
Keyword(s):  
Coronal Mass Ejections ◽  
Large Scale ◽  
Electron Flux ◽  
Energetic Electron ◽  
Radial Distance ◽  
Wave Power ◽  
Electron Content ◽  
Interplanetary Coronal Mass Ejections ◽  
Outer Radiation Belt ◽  
The Earth

Abstract. The energetic electron content in the Van Allen radiation belts surrounding the Earth can vary dramatically on several timescales, and these strong electron fluxes present a hazard for spacecraft traversing the belts. The belt response to solar wind driving is yet largely unpredictable and especially the direct response to specific large-scale heliospheric structures has not been considered previously. We investigate the immediate response of electron fluxes in the outer belt to driving by sheath regions preceding interplanetary coronal mass ejections and the associated wave activity in the inner magnetosphere. We consider events from 2012 to 2018 in the Van Allen Probes era to employ the energy and radial distance resolved electron flux observations of the twin spacecraft mission. We perform a statistical study of the events using superposed epoch analysis, where the sheaths are superposed separately from the ejecta and resampled to the same average duration. Our results show that wave power of ultra-low frequency Pc5 and electromagnetic ion cyclotron waves, as measured by a geostationary GOES satellite, is higher during the sheaths than during the ejecta. However, the level of chorus wave power remains approximately the same, despite on average stronger ring current enhancements during the ejecta. Electron flux enhancements are common at low energies ( 4). Distinctively, depletion extends to lower energies at larger distances. We suggest that this L-shell and energy dependent depletion results from magnetopause shadowing dominating the losses at large distances, while wave-particle interactions dominate closer to the Earth. We also show that non-geoeffective sheaths cause significant changes in the outer belt electron fluxes.

Peculiarities of the outer radiation belt dynamics during the strong magnetic storm of May 15, 2005

2007 ◽  
Vol 47 (6) ◽  
pp. 696-703 ◽  
Author(s):  
L. V. Tverskaya ◽  
E. A. Ginzburg ◽  
T. A. Ivanova ◽  
N. N. Pavlov ◽  
P. M. Svidsky
Keyword(s):  
Magnetic Storm ◽  
Radiation Belt ◽  
Outer Radiation Belt ◽  
Strong Magnetic Storm

scholarly journals Comparison of energetic ions in cusp and outer radiation belt

2005 ◽  
Vol 110 (A12) ◽  
Author(s):  
Jiasheng Chen ◽  
Theodore A. Fritz ◽  
Robert B. Sheldon
Keyword(s):  
Radiation Belt ◽  
Outer Radiation Belt ◽  
Energetic Ions
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