Flux dropouts of plasma and energetic particles at geosynchronous orbit during large geomagnetic storms: Entry into the lobes

1995 ◽  
Vol 100 (A5) ◽  
pp. 8031 ◽  
Author(s):  
Mark B. Moldwin ◽  
Michelle F. Thomsen ◽  
Samuel J. Bame ◽  
David J. McComas ◽  
Joachim Birn ◽  
...  
Keyword(s):  
Geomagnetic Storms ◽  
Energetic Particles ◽  
Geosynchronous Orbit

scholarly journals Association of cusp energetic ions with geomagnetic storms and substorms

2012 ◽  
Vol 30 (12) ◽  
pp. 1633-1643 ◽  
Author(s):  
J. T. Niehof ◽  
S. K. Morley ◽  
R. H. W. Friedel
Keyword(s):  
Geomagnetic Storm ◽  
Geomagnetic Storms ◽  
Energetic Particles ◽  
Energetic Ions ◽  
Significant Dependence ◽  
Substorm Activity ◽  
Storms And Substorms ◽  
Magnetospheric Dynamics ◽  
Substorm Onsets ◽  
Polar Satellite

Abstract. Energetic ions observed in the cusp have been explained as a result of processes within the magnetosphere, but also proposed as a driver of some of those same processes. This study assesses potential connections between energetic ions observed in the cusp and geomagnetic storm and substorm activity. These connections may suggest sources of cusp energetic particles (CEPs), or imply effects of these particles on magnetospheric dynamics. We identify CEPs from six years of cusp crossings by the Polar satellite, relating them to storm and substorm onsets. CEPs showed no significant dependence on storms but did show a weak, statistically significant, increase after substorm onsets. CEPs had no significant association with subsequent storm or substorm onsets. We conclude that substorm acceleration may contribute to CEPs but CEPs are unlikely to contribute to global magnetospheric dynamics.

scholarly journals Storm-time ionization enhancements at the topside low-latitude ionosphere

2008 ◽  
Vol 26 (4) ◽  
pp. 867-876 ◽  
Author(s):  
A. Dmitriev ◽  
H.-C. Yeh
Keyword(s):  
Radiation Belt ◽  
Temporal Dynamics ◽  
Geomagnetic Storms ◽  
Energetic Particles ◽  
Low Latitude ◽  
Ion Density ◽  
Low Latitude Ionosphere ◽  
Using Data ◽  
Mev Protons ◽  
Earth Radiation

Abstract. Ion density enhancements at the topside low-latitude ionosphere during a Bastille storm on 15–16 July 2000 and Halloween storms on 29–31 October 2003 were studied using data from ROCSAT-1/IPEI experiment. Prominent ion density enhancements demonstrate similar temporal dynamics both in the sunlit and in the nightside hemispheres. The ion density increases dramatically (up to two orders of magnitude) during the main phase of the geomagnetic storms and reaches peak values at the storm maximum. The density enhancements are mostly localized in the region of a South Atlantic Anomaly (SAA), which is characterized by very intense fluxes of energetic particles. The dynamics of near-Earth radiation was studied using SAMPEX/LEICA data on >0.6 MeV electrons and >0.8 MeV protons at around 600 km altitude. During the magnetic storms the energetic particle fluxes in the SAA region and in its vicinity increase more than three orders of magnitude. The location of increased fluxes overlaps well with the regions of ion density enhancements. Two mechanisms were considered to be responsible for the generation of storm-time ion density enhancements: prompt penetration of the interplanetary electric field and abundant ionization of the ionosphere by enhanced precipitation of energetic particles from the radiation belt.

scholarly journals Neural network prediction of relativistic electrons at geosynchronous orbit during the storm recovery phase: effects of recurring substorms

2002 ◽  
Vol 20 (7) ◽  
pp. 947-951 ◽  
Author(s):  
M. Fukata ◽  
S. Taguchi ◽  
T. Okuzawa ◽  
T. Obara
Keyword(s):  
Neural Network ◽  
Relativistic Electron ◽  
Electron Flux ◽  
Geomagnetic Storms ◽  
Recovery Phase ◽  
Space Environment ◽  
Geosynchronous Orbit ◽  
Neural Network Models ◽  
Magnetospheric Configuration And Dynamics ◽  
Input Parameters

Abstract. During the recovery phase of geomagnetic storms, the flux of relativistic (>2 MeV) electrons at geosynchronous orbits is enhanced. This enhancement reaches a level that can cause devastating damage to instruments on satellites. To predict these temporal variations, we have developed neural network models that predict the flux for the period 1–12 h ahead. The electron-flux data obtained during storms, from the Space Environment Monitor on board a Geostationary Meteorological Satellite, were used to construct the model. Various combinations of the input parameters AL, SAL, Dst and SDst were tested (where S denotes the summation from the time of the minimum Dst). It was found that the model, including SAL as one of the input parameters, can provide some measure of relativistic electron-flux prediction at geosynchronous orbit during the recovery phase. We suggest from this result that the relativistic electron-flux enhancement during the recovery phase is associated with recurring substorms after Dst minimum and their accumulation effect.Key words. Magnetospheric physics (energetic particles, trapped; magnetospheric configuration and dynamics; storms and substorms)

scholarly journals Strong southward and northward currents observed in the inner plasma sheet

2019 ◽  
Vol 37 (5) ◽  
pp. 931-941
Author(s):  
Yan-Yan Yang ◽  
Chao Shen ◽  
Yong Ji
Keyword(s):  
Magnetic Field ◽  
Plasma Sheet ◽  
Geomagnetic Storms ◽  
Energetic Particles ◽  
Inner Magnetosphere ◽  
Function Analyzer ◽  
Cluster Ion ◽  
Energetic Particle Flux ◽  
Field Lines ◽  
The Magnetic Field

Abstract. It is generally believed that field-aligned currents (FACs) and the ring current (RC) are two dominant parts of the inner magnetosphere. However, using the Cluster spacecraft crossing the pre-midnight inner plasma sheet in the latitudinal region between 10 and 30∘ N, it is found that, during intense geomagnetic storms, in addition to FACs and the RC, strong southward and northward currents also exist which should not be FACs because the magnetic field in these regions is mainly along the x–y plane. Detailed investigation shows that both magnetic-field lines (MFLs) and currents in these regions are highly dynamic. When the curvature of MFLs changes direction in the x–y plane, the current also alternatively switches between being southward and northward. To investigate the generation mechanism of the southward and northward current, we employed the analysis of energetic particle flux up to 1 MeV. For energetic particles below 40 keV, observations from Cluster CIS/CODIF (Cluster Ion Spectrometry COmposition and DIstribution Function analyzer) are used. However, for higher-energy particles, the flux is obtained by extrapolations of low-energy particle data through Kappa distribution. The result indicates that the most reasonable cause of these southward and northward currents is the curvature drift of energetic particles.

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