scholarly journals The Role of the Dynamic Plasmapause in Outer Radiation Belt Electron Flux Enhancement

2020 ◽  
Vol 47 (7) ◽  
Author(s):  
M. Bruff ◽  
A. N. Jaynes ◽  
H. Zhao ◽  
J. Goldstein ◽  
D. M. Malaspina ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Electron Flux ◽  
Outer Radiation Belt ◽  
Flux Enhancement

scholarly journals Medium Energy Electron Flux in Earth's Outer Radiation Belt (MERLIN): A Machine Learning Model

2020 ◽  
Author(s):  
Artem Smirnov ◽  
Max Berrendorf ◽  
Yuri Shprits ◽  
Elena A. Kronberg ◽  
Hayley J Allison ◽  
...  
Keyword(s):  
Machine Learning ◽  
Radiation Belt ◽  
Electron Flux ◽  
Learning Model ◽  
Energy Electron ◽  
Medium Energy ◽  
Outer Radiation Belt ◽  
Machine Learning Model

scholarly journals Electron flux enhancement in the inner radiation belt during moderate magnetic storms

2007 ◽  
Vol 25 (6) ◽  
pp. 1359-1364 ◽  
Author(s):  
H. Tadokoro ◽  
F. Tsuchiya ◽  
Y. Miyoshi ◽  
H. Misawa ◽  
A. Morioka ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Electron Flux ◽  
Recovery Phase ◽  
Magnetic Activity ◽  
Magnetic Storms ◽  
Natural Phenomena ◽  
Early Recovery ◽  
Flux Enhancement ◽  
Angle Scattering ◽  
Order Of Magnitude

Abstract. During moderate magnetic storms, an electron channel (300–1100 keV) of the NOAA satellite has shown sudden electron flux enhancements in the inner radiation belt. After examinating the possibility of contamination by different energetic particles, we conclude that these electron flux enhancements are reliable enough to be considered as natural phenomena, at least for the cases of small to moderate magnetic storms. Here, we define small and moderate storms to be those in which the minimum Dst ranges between −30 and −100 nT. The electron flux enhancements appear with over one order of magnitude at L~2 during these storms. The enhancement is not accompanied by any transport of electron flux from the outer belt. Statistical analysis shows that these phenomena have a duration of approximately 1 day during the period, starting with the main phase to the early recovery phase of the storms. The flux enhancement shows a dawn-dusk asymmetry; the amount of increased flux is larger in the dusk side. We suggest that this phenomenon could not be caused by the radial diffusion but would be due to pitch-angle scattering at the magnetic equator. The inner belt is not in a stationary state, as was previously believed, but is variable in response to the magnetic activity.

The dynamics of the inner boundary of the outer radiation belt during geomagnetic storms

2020 ◽  
Author(s):  
Xiaofei Shi ◽  
Jie Ren ◽  
Qiugang Zong
Keyword(s):  
Radiation Belt ◽  
Electron Flux ◽  
Geomagnetic Storms ◽  
Minimum Energy ◽  
Onset Time ◽  
Recovery Phase ◽  
Outer Radiation Belt ◽  
H Index ◽  
Late Recovery ◽  
Energy Dependent

<p>We present a statistical study of energy-dependent and L shell-dependent inner boundary of the outer radiation belt during 37 isolated geomagnetic storms using observations from Van Allen Probes from 2013 to 2017. There are mutual transformations between "V-shaped" and "S-shaped" inner boundaries during different storm phases, resulting from the competition among electron loss, radial transport and local acceleration. The radial position, onset time, E<sub>st</sub> (the minimum energy at L<sub>st</sub> where the inner boundary starts to exhibit an S-shaped form), and the radial width of S-shaped boundary (ΔL) are quantitatively defined according to the formation of a reversed energy spectrum (electron flux going up with increasing energies from hundreds of keV to ~1 MeV) from a kappa-like spectrum (electron flux steeply falling with increasing energies). The case and statistical results present that (1) The inner boundary has repeatable features associated with storms: the inner boundary is transformed from S-shaped to V-shaped form in several hours during the storm commencement and main phase, and retains in the V-shaped form for several days until it evolves into S-shaped during late recovery phase; (2) ΔL shows positive correlation with SYM-H index; (3) The duration of the V-shaped form is positively correlated with the storm intensity and the duration of the recovery phase; (4) The minimum energy E<sub>st</sub> are mainly distributed in the range of 100-550 keV. All these findings have important implications for understanding the dynamics of energetic electrons in the slot region and the outer radiation belt during geomagnetic storms.</p>

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>

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