scholarly journals On the origin of plasma sheet reconfiguration during the substorm growth phase

2017 ◽  
Vol 44 (17) ◽  
pp. 8696-8702 ◽  
Author(s):  
Evgeny Gordeev ◽  
Victor Sergeev ◽  
Viacheslav Merkin ◽  
Maria Kuznetsova
Keyword(s):  
Growth Phase ◽  
Plasma Sheet

A 2-D empirical plasma sheet pressure model for substorm growth phase using the Support Vector Regression Machine

2015 ◽  
Vol 120 (3) ◽  
pp. 1957-1973 ◽  
Author(s):  
Chao Yue ◽  
Chih-Ping Wang ◽  
Larry Lyons ◽  
Yongli Wang ◽  
Tung-Shin Hsu ◽  
...  
Keyword(s):  
Support Vector Regression ◽  
Growth Phase ◽  
Plasma Sheet ◽  
Support Vector

scholarly journals Average characteristics of the midtail plasma sheet in different dynamic regimes of the magnetosphere

2004 ◽  
Vol 22 (6) ◽  
pp. 2107-2113 ◽  
Author(s):  
N. P. Dmitrieva ◽  
V. A. Sergeev ◽  
M. A. Shukhtina
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Growth Phase ◽  
Plasma Sheet ◽  
Transfer Rate ◽  
Flux Transport ◽  
Data Set ◽  
Magnetospheric Convection ◽  
Flux Transfer ◽  
Night Flux

Abstract. We study average characteristics of plasma sheet convection in the middle tail during different magnetospheric states (Steady Magnetospheric Convection, SMC, and substorms) using simultaneous magnetotail (Geotail, 15-35 RE downtail) and solar wind (Wind spacecraft) observations during 3.5 years. (1) A large data set allowed us to obtain the average values of the plasma sheet magnetic flux transfer rate (Ey and directly compare it with the dayside transfer rate (Emod for different magnetospheric states. The results confirm the magnetic flux imbalance model suggested by Russell and McPherron (1973), namely: during SMC periods the day-to-night flux transport rate equals the global Earthward plasma sheet convection; during the substorm growth phase the plasma sheet convection is suppressed on the average by 40%, whereas during the substorm expansion phase it twice exceeds the day-to-night global flux transfer rate. (2) Different types of substorms were revealed. About 1/3 of all substorms considered displayed very weak growth in the tail lobe magnetic field before the onset. For these events the plasma sheet transport was found to be in a balance with the day-to-night flux transfer, as in the SMC events. However, the lobe magnetic field value in these cases was as large as that in the substorms with a classic growth phase just before the onset (both values exceed the average level of the lobe field during the SMC). Also, in both groups similar configurational changes (magnetic field stretching and plasma sheet thinning) were observed before the substorm onset. (3) Superimposed epoch analysis showed that the plasma sheet during the late substorm recovery phase has the characteristics similar to those found during SMC events, the SMC could be a natural magnetospheric state following the substorm.

Current sheet thickness in the near-Earth plasma sheet during substorm growth phase

1990 ◽  
Vol 95 (A4) ◽  
pp. 3819 ◽  
Author(s):  
V. A. Sergeev ◽  
P. Tanskanen ◽  
K. Mursula ◽  
A. Korth ◽  
R. C. Elphic
Keyword(s):  
Current Sheet ◽  
Growth Phase ◽  
Plasma Sheet ◽  
Sheet Thickness

scholarly journals Transition from substorm growth to substorm expansion phase as observed with a radial configuration of ISTP and Cluster spacecraft

2005 ◽  
Vol 23 (6) ◽  
pp. 2183-2198 ◽  
Author(s):  
V. A. Sergeev ◽  
M. V. Kubyshkina ◽  
W. Baumjohann ◽  
R. Nakamura ◽  
O. Amm ◽  
...  
Keyword(s):  
Transition Region ◽  
Growth Phase ◽  
Plasma Sheet ◽  
Magnetic Energy ◽  
Global Scale ◽  
Substorm Onset ◽  
Plasma Injection ◽  
Storms And Substorms ◽  
Auroral Phenomena ◽  
Inner Region

Abstract. Transition from the growth phase to the substorm expansion during a well-isolated substorm with a strong growth phase is investigated using a unique radial (THEMIS-like) spacecraft constellation near midnight, including the probing of the tail current at ~16 RE with Cluster, of the transition region at ~9 RE with Geotail and Polar, and of the inner region at 6.6 RE with two LANL spacecraft. The activity development on both a global scale and near the spacecraft footpoints was monitored with global auroral images (from the IMAGE spacecraft) and the ground network. Magnetospheric models, tuned using in-situ observations, indicated a strong tail stretching and plasma sheet thinning, which included the growth of the near-Earth current (approaching 30 nA/m2) and possible formation of a local B minimum in the neutral sheet (~5 nT) at ~10–12 RE near the substorm onset. However, there were no indications that the substorm onset was initiated just in this region. We emphasize the rather weak magnetic and plasma flow perturbations observed outside the thinned plasma sheet at Cluster, which could be interpreted as the effects of localized earthward-contracting newly-reconnected plasma tubes produced by the impulsive reconnection in the midtail plasma sheet. In that case the time delays around the distinct substorm onset are consistent with the activity propagation from the midtail to the inner magnetosphere. A peculiar feature of this substorm was that 12min prior to this distinct onset, a clear soft plasma injection to the GEO orbit was recorded which has little associated effects both in the ionosphere and in the transition region at ~9 RE. This pseudo-breakup was probably due to either a localized ballooning-type activity or due to the braking of a very narrow BBF whose signatures were also recorded by Cluster. This event manifested the (previously unknown) phenomenon, a strong tail overloading (excessive storage of magnetic energy) contrasted to the modest energy dissipation and plasma acceleration, which are both discussed and interpreted as the consequences of cold/dense and thick pre-substorm plasma sheet which often occurs after the long quiet period. The lessons of using the radial spacecraft configurations in substorm onset studies are also discussed. Keywords. Magnetospheric physics (Auroral phenomena, plasma sheet, storms and substorms)

Sign in / Sign up

Export Citation Format

Share Document