OBSERVATIONS OF SUBSTORM ACTIVITY FROM THE DATA OF MAIN CAMERA SYSTEM AND THD SATELLITE IN THE PLASMA SHEET

2021 ◽  
Vol 44 ◽  
pp. 16-19
Author(s):  
I.V. Despirak ◽  
◽  
T.V. Kozelova ◽  
B.V. Kozelov ◽  
A.A. Lubchich ◽  
...  
Keyword(s):  
Kola Peninsula ◽  
Growth Phase ◽  
Plasma Sheet ◽  
Space Time ◽  
Interesting Case ◽  
Camera System ◽  
Expansion Phase ◽  
Energetic Electrons ◽  
Time Dynamics ◽  
Substorm Activity

We investigated an interesting case of the space-time dynamics of substorm activations (AL ~ 800 nT) on December 24, 2014, when there were simultaneous observations on the THEMIS D satellite in the plasma sheet (|X| ~ 6.2 RE) and ground-based observations on the Kola Peninsula. The development of the substorm activity in the interval of ~ 19:00 to ~ 20:00 UT was considered. In this interval, at Lovozero station (LOZ), three peaks in the Pi1B pulsations were recorded, associated with the brightening of arcs near LOZ. The first peak was observed in connection with the appearance of beads structures in the auroras along the growth phase arc to the south from LOZ latitude. The second and third peaks in Pi1B pulsations were associated with the expansion phase, when three dipolarization fronts (DFs) were registered according THD data. DFs and injection of energetic electrons into the magnetosphere were observed near the moments of sudden intensification of auroras: brightening of arcs, breakup in aurora. Besides, it was shown that the development of substorm occurs near the Harang discontinuity (HD) according to the IMAGE magnetometers data. In this case, we can follow the development of aurora around the HD according to the data of the all sky camera in Apatity. It was shown that the pre-onset auroral forms were moved accordingly the two-cell ionospheric convection developed during the growth phase of the substorm.

scholarly journals Studies of magnetotail dynamics and energy evolution during substorms using MHD simulations

2009 ◽  
Vol 27 (4) ◽  
pp. 1717-1727 ◽  
Author(s):  
S. Brogl ◽  
R. E. Lopez ◽  
M. Wiltberger ◽  
H. K. Rassoul
Keyword(s):  
Growth Phase ◽  
Plasma Sheet ◽  
Magnetic Energy ◽  
Substorm Onset ◽  
Energy Evolution ◽  
Polar Cap ◽  
Expansion Phase ◽  
Mhd Simulations ◽  
Hydrodynamic Code ◽  
Magnetotail Dynamics

Abstract. We examine the distribution and propagation of energy in the plasma sheet and lobes using observations and simulations for three substorms. The substorms occurred on 9 March 1995, 10 December 1996, and 27 August 2001 and have been simulated using the Lyon-Fedder-Mobarry magneto-hydrodynamic code. All three events occur over North America and show a clear substorm current wedge over the ground magnetometer chains of Alaska, Canada, and Greenland. The three simulations show the thinning of the plasma sheet during the growth phase of the event and an increase in the relative amount of thermal energy due to the compression of the plasma sheet. Generally, the total lobe energy, polar cap flux, and lobe magnetic field strength simultaneously increase during the growth phase, and polar cap flux and total lobe energy only start dropping at substorm onset, as measured by the CANOPUS magnetometer chain. Starting at time of onset and continuing throughout the expansion phase a transfer of magnetic energy from the lobes into the plasma sheet occurs, with the increase in the plasma sheet energy ranging from 30–40% of the energy that is released from the lobes.

Fitting partial differential equations to space-time dynamics

1999 ◽  
Vol 59 (1) ◽  
pp. 337-342 ◽  
Author(s):  
Markus Bär ◽  
Rainer Hegger ◽  
Holger Kantz
Keyword(s):  
Partial Differential Equations ◽  
Differential Equations ◽  
Space Time ◽  
Partial Differential ◽  
Time Dynamics

scholarly journals Space-time dynamics estimation from space mission tracking data

2016 ◽  
Vol 587 ◽  
pp. A156 ◽  
Author(s):  
D. Dirkx ◽  
R. Noomen ◽  
P. N. A. M. Visser ◽  
L. I. Gurvits ◽  
L. L. A. Vermeersen
Keyword(s):  
Space Mission ◽  
Space Time ◽  
Tracking Data ◽  
Time Dynamics

scholarly journals On energetic electrons (>38 keV) in the central plasma sheet: Data analysis and modeling

2011 ◽  
Vol 116 (A9) ◽  
pp. n/a-n/a ◽  
Author(s):  
Bingxian Luo ◽  
Weichao Tu ◽  
Xinlin Li ◽  
Jiancun Gong ◽  
Siqing Liu ◽  
...  
Keyword(s):  
Data Analysis ◽  
Plasma Sheet ◽  
Energetic Electrons ◽  
Central Plasma ◽  
Central Plasma Sheet

scholarly journals Pulsating aurora and cosmic noise absorption associated with growth-phase arcs

2018 ◽  
Vol 36 (1) ◽  
pp. 59-69 ◽  
Author(s):  
Derek McKay ◽  
Noora Partamies ◽  
Juha Vierinen
Keyword(s):  
Growth Phase ◽  
Optical Emission ◽  
Border Region ◽  
Emission Region ◽  
Expansion Phase ◽  
Phase Dynamics ◽  
Noise Absorption ◽  
Initial Stage ◽  
Cosmic Noise

Abstract. The initial stage of a magnetospheric substorm is the growth phase, which typically lasts 1–2 h. During the growth phase, an equatorward moving, east–west extended, optical auroral arc is observed. This is called a growth-phase arc. This work aims to characterize the optical emission and riometer absorption signatures associated with growth-phase arcs of isolated substorms. This is done using simultaneous all-sky camera and imaging riometer observations. The optical and riometric observations allow determination of the location of the precipitation within growth-phase arcs of low- (<10  keV) and high- (> 10 keV) energy electrons, respectively. The observations indicate that growth-phase arcs have the following characteristics: The peak of the cosmic noise absorption (CNA) arc is equatorward of the optical emission arc. This CNA is contained within the region of diffuse aurora on the equatorward side. Optical pulsating aurora are seen in the border region between the diffuse emission region on the equatorward side and the bright growth-phase arc on the poleward side. CNA is detected in the same region. There is no evidence of pulsations in the CNA. Once the equatorward drift starts, it proceeds at constant speed, with uniform separation between the growth-phase arc and CNA of 40±10 km. Optical pulsating aurora are known to be prominent in the post-onset phase of a substorm. The fact that pulsations are also seen in a fairly localized region during the growth phase shows that the substorm expansion-phase dynamics are not required to closely precede the pulsating aurora. Keywords. Ionosphere (auroral ionosphere)

MANIPULATING PLANAR SHAPES WITH A LIGHT-SENSITIVE EXCITABLE MEDIUM: COMPUTATIONAL STUDIES OF CLOSED-LOOP SYSTEMS

2006 ◽  
Vol 16 (08) ◽  
pp. 2333-2349 ◽  
Author(s):  
SERGEY SKACHEK ◽  
ANDREW ADAMATZKY ◽  
CHRIS MELHUISH
Keyword(s):  
Closed Loop ◽  
Space Time ◽  
Excitable Medium ◽  
Computational Studies ◽  
Wave Fronts ◽  
Nonlinear Media ◽  
Time Dynamics ◽  
Distributed Manipulation ◽  
Closed Loop Systems ◽  
Planar Shapes

We study how to employ space-time dynamics in nonlinear media to achieve distributed manipulation of objects — positioning, orienting and transporting objects by wave-fronts and patterns in excitable medium. We present the results of computational experiments of a massive parallel actuator controlled by a cellular-automaton model of an excitable medium. The model incorporates closed-loop actuation where sites of the medium can be excited not only by their closest neighbors but also by the edges of the manipulated object. We analyze motion of basic planar shapes (either initially aligned along axes or randomly oriented) induced by an actuator controlled by excitable lattice with various excitation rules. We demonstrate that space-time excitation dynamics in discrete nonlinear media bears a huge potential in terms of sensible nontrivial manipulation of planar shapes.

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