scholarly journals Statistical Study of Selective Oxygen Increase in High‐Energy Ring Current Ions During Magnetic Storms

2019 ◽  
Vol 124 (5) ◽  
pp. 3193-3209 ◽  
Author(s):  
K. Mitani ◽  
K. Seki ◽  
K. Keika ◽  
M. Gkioulidou ◽  
L. J. Lanzerotti ◽  
...  
Keyword(s):  
Ring Current ◽  
Statistical Study ◽  
High Energy ◽  
Magnetic Storms

Survey of Ring Current Composition During Magnetic Storms

1998 ◽  
Author(s):  
M. Grande ◽  
C. H. Perry ◽  
A. Hall ◽  
J. Fennell ◽  
B. Wilken
Keyword(s):  
Ring Current ◽  
Magnetic Storms

Analysis of Magnetic Storms withDRIndices for Equatorial Ring-Current Field

Radio Science ◽  
1971 ◽  
Vol 6 (2) ◽  
pp. 277-278 ◽  
Author(s):  
Yohsuke Kamide ◽  
Naoshi Fukushima
Keyword(s):  
Ring Current ◽  
Magnetic Storms ◽  
Current Field

scholarly journals Dual source populations of substorm-associated ring current ions

2009 ◽  
Vol 27 (4) ◽  
pp. 1431-1438 ◽  
Author(s):  
M. Yamauchi ◽  
Y. Ebihara ◽  
I. Dandouras ◽  
H. Rème
Keyword(s):  
Ring Current ◽  
Early Morning ◽  
High Energy ◽  
Low Energy ◽  
Narrow Energy Range ◽  
Different Temperatures ◽  
Energy Domain ◽  
Dual Source ◽  
Cold Component ◽  
Source Populations

Abstract. Sources of low-energy ring current ions in the early morning sector (eastward drifting energy domain of about <5 keV) are examined using both statistical analyses and numerical tracing methods (phase-space mapping and simulation). In about 90% of Cluster perigee traversals at 02~07 local time, these low-energy ring current ions have dual ion populations: one is wedge-like energy-dispersed ions, and the other is a band-like ions over different latitudes in a narrow energy range at the upper energy threshold of the wedge-like energy-dispersed ions. Both components are most likely created during past substorm activities. Numerical tracing results strongly suggest that these two components have different sources with different temperatures and elapsed times. The band-like part most likely comes from ions with plasma sheet temperature (~1 keV), and the energy-dispersed part most likely comes from cold ions (temperature <0.1 keV). The source density of the cold component (0.2~0.5×106/m3) is slightly less than that of the hot component (0.5×106/m3), while Cluster observation shows slightly higher density for the wedge-like part than the low-energy band-like part. The hot source component also explains the observed high-energy (>10 keV) ions drifting westward after adiabatic energization in the nightside under time-varying electric field. The wedge-like part has much shorter elapsed time, i.e., less charge-exchange loss, than the band-like part.

The MLT distribution and detailed structure of ring current:  MMS observations

2021 ◽  
Author(s):  
Xin Tan ◽  
Malcolm Dunlop ◽  
Xiangcheng Dong ◽  
Yanyan Yang ◽  
Christopher Russell
Keyword(s):  
Current Density ◽  
Large Scale ◽  
Ring Current ◽  
Current System ◽  
Radial Profile ◽  
Three Dimensional ◽  
Current Density Distribution ◽  
Magnetic Storms ◽  
In Situ Data

&lt;p&gt;The ring current is an important part of the large-scale magnetosphere-ionosphere current system; mainly concentrated in the equatorial plane, between 2-7 R&lt;sub&gt;E&lt;/sub&gt;, and strongly ordered between &amp;#177; 30 &amp;#176; latitude. The morphology of ring current directly affects the geomagnetic field at low to middle latitudes. Rapid changes in ring current densities can occur during magnetic storms/sub-storms. Traditionally, the Dst index is used to characterize the intensity of magnetic storms and to reflect the variation of ring current intensity, but this index does not reflect the MLT distribution of ring current. In fact, the ring current has significant variations with MLT, depending on geomagnetic activity, due to the influence of multiple factors; such as, the partial ring current, region 1/region 2 field-aligned currents, the magnetopause current and sub-storm cycle (magnetotail current). The form of the ring current has been inferred from the three-dimensional distribution of ion differential fluxes from neutral atom imaging; however, this technique can not directly obtain the current density distribution (as can be obtained using multi-spacecraft in situ data). Previous in situ estimates of current density have used: Cluster, THEMIS and other spacecraft groups to study the distribution of the ring current for limited ranges of either radial profile, or MLT and MLAT variations. Here, we report on an extension to these studies using FGM data from MMS obtained during the period September 1, 2015 to December 31, 2016, when the MMS orbit and configuration provided good coverage. We employ the curlometer method to calculate the current density, statistically, to analysis the MLT distribution according to different geomagnetic conditions. Our results show the clear asymmetry of the ring current and its different characteristics under different geomagnetic conditions.&lt;/p&gt;

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