Evolution of the low-latitude geomagnetic storm field and the importance of turbulent diffusion for ring current particle losses

1996 ◽  
Vol 101 (A11) ◽  
pp. 24689-24706 ◽  
Author(s):  
A. Grafe ◽  
V. Y. Trakhtengerts ◽  
P. A. Bespalov ◽  
A. G. Demekhov
Keyword(s):  
Geomagnetic Storm ◽  
Turbulent Diffusion ◽  
Ring Current ◽  
Low Latitude

scholarly journals Discovering the Low-Latitude Ionospheric Trough Associated With the Inner Radiation Belt

2021 ◽  
Author(s):  
Alexander Karpachev
Keyword(s):  
Geomagnetic Storm ◽  
Radiation Belt ◽  
Ring Current ◽  
Recovery Phase ◽  
Low Latitude ◽  
Champ Satellite ◽  
Main Ionospheric Trough ◽  
Long Time ◽  
Late Recovery ◽  
First Time

Abstract The dynamics of ionospheric troughs during great geomagnetic storm on April 11–13, 2001 is considered. An analysis is based on measurements of electron density at altitudes of the CHAMP satellite 410–465 km. The subauroral, mid-latitude and low-latitude troughs were observed at nighttime, sometimes simultaneously. The subauroral trough is usually defined as the main ionospheric trough. The mid-latitude trough is associated with the magnetospheric ring current. It appears at the beginning of the storm recovery phase at latitudes of 40–45° GMLat (L=1.7–2.0) and exists for a long time at the late recovery phase at latitudes of the residual ring current 50–55° GMLat (L~2.4–3.0). The low-latitude trough was revealed for the first time. It is developed at the latitudes of the inner radiation belt 34–45° GMLat (L=1.45–2.00). This trough is associated with the precipitation of energetic particles from the inner radiation belt.

scholarly journals Discovery of a low-latitude ionospheric trough associated with the inner radiation belt

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. T. Karpachev
Keyword(s):  
Geomagnetic Storm ◽  
Radiation Belt ◽  
Ring Current ◽  
Recovery Phase ◽  
Low Latitude ◽  
Champ Satellite ◽  
Long Period ◽  
Main Ionospheric Trough ◽  
Late Recovery ◽  
First Time

AbstractThe dynamics of ionospheric troughs that developed during a great geomagnetic storm on 11–13 April 2001 are studied using measurements of electron density obtained by the CHAMP satellite at an altitude of 410–465 km. Subauroral, mid-latitude and low-latitude troughs were observed at nighttime, sometimes simultaneously. The subauroral trough is usually defined as the main ionospheric trough, whereas the mid-latitude trough is associated with the magnetospheric ring current. It appeared at the beginning of the storm recovery phase around latitudes of 40°–45° GMLat (L = 1.7–2.0) and existed for a long period of time throughout the late recovery phase of the residual ring current at latitudes of 50°–55° GMLat (L ~ 2.4–3.0). For the first time, a low-latitude trough was revealed. It developed at latitudes of 34°–45° GMLat (L = 1.45–2.00) in association with the precipitation of energetic particles from the inner radiation belt.

scholarly journals Simulation study of the energetic neutral atom (ENA) imaging monitoring of the geomagnetosphere on a lunar base

2021 ◽  
Vol 7 (3) ◽  
pp. 3-11
Author(s):  
Lu Li ◽  
Yu Qing-Long ◽  
Zhou Ping ◽  
Zhang Xin ◽  
Zhang Xian-Guo ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Ring Current ◽  
Sampling Interval ◽  
Base Station ◽  
Radiation Environment ◽  
Emission Model ◽  
The Moon ◽  
Imaging Data ◽  
Particle Radiation ◽  
Energy Channel

Since the moon’s revolution cycle is exactly the same as its rotation cycle, we can only see the moon always facing Earth in the same direction. Based on the clean particle radiation environment of the moon, a neutral atomic telemetry base station could be established on the lunar surface facing Earth to realize long-term continuous geomagnetic activity monitoring. Using the 20°×20° field of view, the 0.5°×0.5° angle resolution, and the ~0.17 cm²sr geometric factor, a two-dimensional ENA imager is being designed. The magnetospheric ring current simulation at a 4–20 keV energy channel for a medium geomagnetic storm (Kp=5) shows the following: 1) at ~60 Rᴇ (Rᴇ is the Earth radius), the imager can collect 10⁴ ENA events for 3 min to meet the statistical requirements for 2D coded imaging data inversion, so as to meet requirements for the analysis of the substorm ring current evolution process of magnetic storms above medium; 2) the ENA radiation loss puzzles in the magnetopause and magnetotail plasma sheet regions have been deduced and revealed using the 2-D ENA emission model. High spatial-temporal resolution ENA imaging monitoring of these two important regions will provide the measurement basis for the solar wind energy input process and generation mechanism; 3) the average sampling interval of ENA particle events is about 16 ms at the moon’s orbit; the spectral time difference for the set energy range is on the order of minutes, which can provide location information to track the trigger of geomagnetic storm particle events.

scholarly journals Middle‐ and low‐latitude ionosphere response to 2015 St. Patrick's Day geomagnetic storm

2016 ◽  
Vol 121 (4) ◽  
pp. 3421-3438 ◽  
Author(s):  
B. Nava ◽  
J. Rodríguez‐Zuluaga ◽  
K. Alazo‐Cuartas ◽  
A. Kashcheyev ◽  
Y. Migoya‐Orué ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Low Latitude ◽  
Low Latitude Ionosphere

Magnetospheric reconfiguration during the substorm cycle as inferred from the data-based modeling.

2021 ◽  
Author(s):  
Nikolai Tsyganenko ◽  
Varvara Andreeva ◽  
Mikhail Sitnov ◽  
Jesper Gjerloev ◽  
Xiangning Chu ◽  
...  
Keyword(s):  
Ring Current ◽  
Full Range ◽  
Temporal Trends ◽  
Basis Functions ◽  
Polar Cap ◽  
Low Latitude ◽  
Quarter Century ◽  
Expansion Phase ◽  
First Results ◽  
The Magnetic Field

<p>First results are presented of reconstructing the evolution of magnetospheric configurations through the full cycle of isolated substorms. The modeling covers the low- and mid-latitude magnetosphere in the range of radial distances from 2 to 20 Re and is based on a synthesis of (1) a high-resolution representation of the magnetic field by cylindrical basis functions, (2) the ever largest pool of magnetospheric and interplanetary data spanning the last quarter century (1995-2019), (3) an archive of concurrent ground-based indices and their temporal trends, quantifying the geomagnetic activity over the full range of latitudes, including the low-latitude ring current SMR-index, the midlatitude positive bay MPB-index, the auroral SML-index, and the polar cap PC-index, (4) the data-mining nearest-neighbour (NN) technique of the data selection and weighting in the geometric and parametric spaces. The obtained successive diagrams of magnetic depression/compression, electric current, and field line maps demonstrate all the typical features of the substorm cycle: the initial relatively slow stretching of the nightside tail during the growth phase, followed by its sudden collapse associated with a dramatic disruption of the tail current at R~11-16 Re, and finally a gradual recovery of the configuration after the expansion phase is over.</p>

PROBLEMS OF THE OUTER RADIATION BELT FORMATION AND TOPOLOGICAL FEATURES OF HIGH LATITUDE MAGNETOSPHERE

2021 ◽  
Vol 44 ◽  
pp. 7-11
Author(s):  
Elena Antonova ◽  
Keyword(s):  
Geomagnetic Storm ◽  
High Latitude ◽  
Radiation Belt ◽  
Ring Current ◽  
Outer Part ◽  
Auroral Oval ◽  
Plasma Pressure ◽  
Relativistic Electrons ◽  
Outer Radiation Belt ◽  
Topological Features

We analyzed the problems of formation of the outer radiation belt (ORB) taking into consideration the latest changes in our understanding of the high-latitude magnetospheric topology. This includes strong evidence that the auroral oval maps to the outer part of the ring current, meanwhile the ORB polar boundary maps inside the auroral oval. Our analysis also includes the variation of the plasma pressure distribution and the time of the acceleration of relativistic electrons during geomagnetic storm. It is shown that the maximum of ORB is formed after the geomagnetic storm in the region of plasma pressure maximum. The position of this maximum agrees with the prediction of the ORB formation theory based on the analysis of ring current development during storm. We emphasize the role of adiabatic processes in the ORB dynamics and the importance of the substorm injections during storm recovery phase for the formation of enhanced fluxes of ORB electrons after the storm.

scholarly journals Longitudinal differences observed in the ionospheric F-region during the major geomagnetic storm of 31 March 2001

2004 ◽  
Vol 22 (9) ◽  
pp. 3221-3229 ◽  
Author(s):  
Y. Sahai ◽  
P. R. Fagundes ◽  
F. Becker-Guedes ◽  
J. R. Abalde ◽  
G. Crowley ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Recovery Period ◽  
Negative Phase ◽  
Quiet Period ◽  
Geomagnetic Disturbances ◽  
Low Latitude ◽  
F Region ◽  
Similarities And Differences ◽  
Worldwide Network ◽  
Ionospheric Sounding

Abstract. A new ionospheric sounding station using a Canadian Advanced Digital Ionosonde (CADI) was established for routine measurements by the "Universidade do Vale do Paraiba (UNIVAP)" at São José dos Campos (23.2° S, 45.9° W), Brazil, in August 2000. A major geomagnetic storm with gradual commencement at about 01:00 UT was observed on 31 March 2001. In this paper, we present and discuss salient features from the ionospheric sounding measurements carried out at S. J. Campos on the three consecutive UT days 30 March (quiet), 31 March (disturbed) and 1 April (recovery) 2001. During most of the storm period, the foF2 values showed negative phase, whereas during the two storm-time peaks, large F-region height variations were observed. In order to study the longitudinal differences observed in the F-region during the storm, the simultaneous ionospheric sounding measurements carried out at S. J. Campos, El Arenosillo (37.1° N, 6.7° W), Spain, Okinawa (26.3° N, 127.8° E), Japan and Wakkanai (45.5° N, 141.7° E), Japan, during the period 30 March-1 April 2001, have been analyzed. A comparison of the observed ionospheric parameters (h'F and foF2) in the two longitudinal zones (1. Japanese and 2. Brazilian-Spanish) shows both similarities and differences associated with the geomagnetic disturbances. Some latitudinal differences are also observed in the two longitudinal zones. In addition, global ionospheric TEC maps from the worldwide network of GPS receivers are presented, showing widespread TEC changes during both the main and recovery phases of the storm. The ionospheric sounding measurements are compared with the ASPEN-TIMEGCM model runs appropriate for the storm conditions. The model results produce better agreement during the quiet period. During the disturbed period, some of the observed F-region height variations are well reproduced by the model results. The model foF2 and TEC results differ considerably during the recovery period and indicate much stronger negative phase at all the stations, particularly at the low-latitude ones.

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