scholarly journals Characteristics of magnetic dipolarizations in the vicinity of the substorm onset region observed by THEMIS

2021 ◽  
Vol 5 (3) ◽  
pp. 239-250
Author(s):  
SuPing Duan ◽  
◽  
Chi Wang ◽  
Weining William Liu ◽  
ZhaoHai He ◽  
...  
Keyword(s):  
Substorm Onset

scholarly journals Decay of the Dst field of geomagnetic disturbance after substorm onset and its implication to storm-substorm relation

1996 ◽  
Vol 14 (6) ◽  
pp. 608-618 ◽  
Author(s):  
T. Iyemori ◽  
D. R. K. Rao
Keyword(s):  
Ring Current ◽  
Geomagnetic Storms ◽  
Sharp Decrease ◽  
Geomagnetic Disturbance ◽  
Substorm Onset ◽  
Significant Development ◽  
H Index ◽  
Magnetospheric Tail ◽  
Storms And Substorms ◽  
Substorm Onsets

Abstract. In order to investigate the causal relationship between magnetic storms and substorms, variations of the mid-latitude geomagnetic indices, ASY (asymmetric part) and SYM (symmetric part), at substorm onsets are examined. Substorm onsets are defined by three different phenomena; (1) a rapid increase in the mid-latitude asymmetric-disturbance indices, ASY-D and ASY-H, with a shape of so-called `mid-latitude positive bay\\'; (2) a sharp decrease in the AL index; (3) an onset of Pi2 geomagnetic pulsation. The positive bays are selected using eye inspection and a pattern-matching technique. The 1-min-resolution SYM-H index, which is essentially the same as the hourly Dst index except in terms of the time resolution, does not show any statistically significant development after the onset of substorms; it tends to decay after the onset rather than to develop. It is suggested by a simple model calculation that the decay of the magnetospheric tail current after substorm onset is responsible for the decay of the Dst field. The relation between the IMF southward turning and the development of the Dst field is re-examined. The results support the idea that the geomagnetic storms and substorms are independent processes; that is, the ring-current development is not the result of the frequent occurrence of substorms, but that of enhanced convection caused by the large southward IMF. A substorm is the process of energy dissipation in the magnetosphere, and its contribution to the storm-time ring-current formation seems to be negligible. The decay of the Dst field after a substorm onset is explained by a magnetospheric energy theorem.

On the three-dimensional magnetic structure of the plasmoid created in the magnetotail at substorm onset

1982 ◽  
Vol 9 (3) ◽  
pp. 203-206 ◽  
Author(s):  
E. W. Hones ◽  
J. Birn ◽  
S. J. Bame ◽  
G. Paschmann ◽  
C. T. Russell
Keyword(s):  
Magnetic Structure ◽  
Three Dimensional ◽  
Substorm Onset

Near-Earth substorm onset: A coordinated study

1994 ◽  
Vol 21 (17) ◽  
pp. 1875-1878 ◽  
Author(s):  
M. A. L. Persson ◽  
H. J. Opgenoorth ◽  
T. I. Pulkkinen ◽  
A. I. Eriksson ◽  
P. O. Dovner ◽  
...  
Keyword(s):  
Substorm Onset

Observations of Changes to the Auroral Distribution Prior to Substorm Onset

2013 ◽  
pp. 257-275 ◽  
Author(s):  
R. D. Elphinstone ◽  
J. S. Murphree ◽  
L. L. Cogger ◽  
D. Hearn ◽  
M. G. Henderson ◽  
...  
Keyword(s):  
Substorm Onset

scholarly journals Pi1B pulsations as a possible driver of Alfvénic aurora at substorm onset

2011 ◽  
Vol 116 (A6) ◽  
pp. n/a-n/a ◽  
Author(s):  
M. R. Lessard ◽  
E. J. Lund ◽  
H. M. Kim ◽  
M. J. Engebretson ◽  
K. Hayashi
Keyword(s):  
Substorm Onset

scholarly journals Determination of substorm onset from the geomagnetic D-perturbation data.

1978 ◽  
Vol 30 (3) ◽  
pp. 187-189 ◽  
Author(s):  
B. L. SHIRMAN ◽  
B. A. UNDSENKOV ◽  
V. A. SHAPIRO
Keyword(s):  
Substorm Onset ◽  
Perturbation Data

scholarly journals Distinction between auroral substorm onset and traditional ground magnetic onset signatures

2013 ◽  
Vol 118 (7) ◽  
pp. 4080-4092 ◽  
Author(s):  
L. R. Lyons ◽  
Y. Nishimura ◽  
E. Donovan ◽  
V. Angelopoulos
Keyword(s):  
Substorm Onset ◽  
Auroral Substorm ◽  
Ground Magnetic

scholarly journals Simultaneous observation of auroral substorm onset in Polar satellite global images and ground-based all-sky images

2018 ◽  
Vol 70 (1) ◽  
Author(s):  
Akimasa Ieda ◽  
Kirsti Kauristie ◽  
Yukitoshi Nishimura ◽  
Yukinaga Miyashita ◽  
Harald U. Frey ◽  
...  
Keyword(s):  
Substorm Onset ◽  
Simultaneous Observation ◽  
Auroral Substorm ◽  
Polar Satellite

Parameters controlling the substorm onset location

2021 ◽  
Author(s):  
Reham Elhawary ◽  
Karl Laundal ◽  
Jone Reistad ◽  
Anders Ohma ◽  
Spencer Hatch ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
Tilt Angle ◽  
Linear Regression Analysis ◽  
Substorm Onset ◽  
Azimuthal Component ◽  
Field Orientation ◽  
Hall Conductance ◽  
Onset Location ◽  
Dipole Tilt

<p>Substorm onset location varies over a range of magnetic local time (MLT) and magnetic latitudes (MLat). It is well known that about 5% of the variation in onset MLT can be explained by variations in interplanetary magnetic field orientation and dipole tilt angle. Both parameters introduce an azimuthal component in the magnetic field in the magnetosphere such that the projection of the onset MLT in the ionosphere is shifted. The MLT of the onset near the magnetopsheric equatorial plane is even less predictable. Recent studies have suggested that gradients in the ionospheric Hall conductance lead to a duskward shift of tail dynamics, which could also influence the location of substorm onset. Our goal is to test these ideas by quantifying the dependence of the spatial variation of the onset location on external and internal conditions. We focus on the correlation between the substorm onset location with conditions prior to the onset, such as the interplanetary magnetic field By component, dipole tilt angle, and estimates of the Hall conductance. Linear regression analysis is used to determine the substorm onset location dependence on the proposed variables.</p>

Sign in / Sign up

Export Citation Format

Share Document