scholarly journals Multi-instrument observations of the electric and magnetic field structure of omega bands

2000 ◽  
Vol 18 (1) ◽  
pp. 99-110 ◽  
Author(s):  
J. A. Wild ◽  
T. K. Yeoman ◽  
P. Eglitis ◽  
H. J. Opgenoorth
Keyword(s):  
Electric Fields ◽  
Time Resolution ◽  
Recovery Phase ◽  
High Time ◽  
High Time Resolution ◽  
Band Formation ◽  
Vhf Radar ◽  
E Region ◽  
Ionospheric Electric Field ◽  
Electric Fields And Currents

Abstract. High time resolution data from the CUTLASS Finland radar during the interval 01:30-03:30 UT on 11 May, 1998, are employed to characterise the ionospheric electric field due to a series of omega bands extending ~5° in latitude at a resolution of 45 km in the meridional direction and 50 km in the azimuthal direction. E-region observations from the STARE Norway VHF radar operating at a resolution of 15 km over a comparable region are also incorporated. These data are combined with ground magnetometer observations from several stations. This allows the study of the ionospheric equivalent current signatures and height integrated ionospheric conductances associated with omega bands as they propagate through the field-of-view of the CUTLASS and STARE radars. The high-time resolution and multi-point nature of the observations leads to a refinement of the previous models of omega band structure. The omega bands observed during this interval have scale sizes ~500 km and an eastward propagation velocity ~0.75 km s-1. They occur in the morning sector (~05 MLT), simultaneously with the onset/intensification of a substorm to the west during the recovery phase of a previous substorm in the Scandinavian sector. A possible mechanism for omega band formation and their relationship to the substorm phase is discussed..Key words. Ionosphere (auroral ionosphere; electric fields and currents) · Magnetospheric physics (magnetosphere-ionosphere interactions)

scholarly journals CUTLASS HF radar observations of high-latitude azimuthally propagating vortical currents in the nightside ionosphere during magnetospheric substorms

2000 ◽  
Vol 18 (6) ◽  
pp. 640-652 ◽  
Author(s):  
J. A. Wild ◽  
T. K. Yeoman
Keyword(s):  
Electric Fields ◽  
Time Resolution ◽  
High Latitude ◽  
High Speed ◽  
Radar Data ◽  
Hf Radar ◽  
High Time ◽  
Vortical Flow ◽  
High Time Resolution ◽  
Magnetospheric Substorms

Abstract. High-time resolution CUTLASS observations and ground-based magnetometers have been employed to study the occurrence of vortical flow structures propagating through the high-latitude ionosphere during magnetospheric substorms. Fast-moving flow vortices (~800 m s-1) associated with Hall currents flowing around upward directed field-aligned currents are frequently observed propagating at high speed (~1 km s-1) azimuthally away from the region of the ionosphere associated with the location of the substorm expansion phase onset. Furthermore, a statistical analysis drawn from over 1000 h of high-time resolution, nightside radar data has enabled the characterisation of the bulk properties of these vortical flow systems. Their occurrence with respect to substorm phase has been investigated and a possible generation mechanism has been suggested.Key words: Ionosphere (auroral ionosphere; electric fields and currents) · Magnetospheric physics (storms and substorms)

scholarly journals Auroral-arc splitting by intrusion of a new convection channel

1996 ◽  
Vol 14 (12) ◽  
pp. 1257-1264 ◽  
Author(s):  
H. U. Frey ◽  
G. Haerendel ◽  
S. Buchert ◽  
B. S. Lanchester
Keyword(s):  
Electric Field ◽  
Time Resolution ◽  
Large Scale ◽  
High Time ◽  
High Time Resolution ◽  
The Common ◽  
The Creation ◽  
Ionospheric Electric Field ◽  
Eiscat Radar ◽  
Uhf Radar

Abstract. During a run of the Common Programme Three of the EISCAT radar the splitting of an auroral arc was observed by high time-resolution, ground-based cameras when the UHF radar beam was close to the arc. The evening eastward electrojet situation with a large-scale northward ionospheric electric field was disturbed by the intrusion of a convection channel with southward electric field from the east. The interaction of the new convection channel with the auroral arc caused changes in arc brightness and arc splitting, i.e. the creation of a new arc parallel to the pre-existing auroral arc. The event is described as one possibility for the creation of parallel arcs during slightly disturbed magnetic conditions far from the Harang discontinuity.

scholarly journals Substorm dynamics revealed by ground observations of two-dimensional auroral structures on 9 October 2000

2005 ◽  
Vol 23 (12) ◽  
pp. 3599-3613 ◽  
Author(s):  
J. Liang ◽  
E. F. Donovan ◽  
G. J. Sofko ◽  
T. Trondsen
Keyword(s):  
Electric Fields ◽  
Time Resolution ◽  
Plasma Sheet ◽  
Wave Activity ◽  
High Time ◽  
Geosynchronous Orbit ◽  
High Time Resolution ◽  
Two Dimensional ◽  
Mode Instability ◽  
The Third

Abstract. Multi-instrument observations of a small substorm event on 9 October 2000 provide, with high time resolution, two-dimensional information about substorm dynamics. A sequence of three optical intensifications, each associated with a Pi2 burst, were found, in which the third auroral intensification marked the onset of a small substorm. All three intensifications originated close to midnight, but evolved progressively eastward. Within each of the three optical intensifications, a few azimuthally-spaced patches appeared, the first one near midnight and the subsequent patches successively eastward in the postmidnight sector, providing evidence for drift wave activity in the near-geosynchronous-orbit plasma sheet (NGOPS). The SuperDARN measurements reveal the development of eastward electric fields at NGOPS latitude within each Pi2 burst interval. These observations can be interpreted as supporting the drift-Alfvén-ballooning (DAB) mode instability and its role in substorm expansion at NGOPS.

Solar Corona Investigation by the Coronal Line Photometer at Lomnický Peak

1994 ◽  
Vol 144 ◽  
pp. 431-434
Author(s):  
M. Minarovjech ◽  
M. Rybanský
Keyword(s):  
Solar Corona ◽  
Time Resolution ◽  
Active Regions ◽  
High Time ◽  
High Time Resolution ◽  
List Type ◽  
Type Number ◽  
Coronal Line ◽  
Global Cycle

AbstractThis paper deals with a possibility to use the ground-based method of observation in order to solve basic problems connected with the solar corona research. Namely:1.heating of the solar corona2.course of the global cycle in the corona3.rotation of the solar corona and development of active regions.There is stressed a possibility of high-time resolution of the coronal line photometer at Lomnický Peak coronal station, and use of the latter to obtain crucial observations.

Discovery of the fast optical variability of GRB 080319B and the prospects for wide-field optical monitoring with high time resolution

2010 ◽  
Vol 180 (4) ◽  
pp. 424 ◽  
Author(s):  
G.M. Beskin ◽  
S.V. Karpov ◽  
S.F. Bondar ◽  
V.L. Plokhotnichenko ◽  
A. Guarnieri ◽  
...  
Keyword(s):  
Time Resolution ◽  
High Time ◽  
High Time Resolution ◽  
Optical Variability ◽  
Wide Field ◽  
Optical Monitoring

scholarly journals Detecting telecom single photons with 99.5−2.07+0.5% system detection efficiency and high time resolution

APL Photonics ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 036114
Author(s):  
J. Chang ◽  
J. W. N. Los ◽  
J. O. Tenorio-Pearl ◽  
N. Noordzij ◽  
R. Gourgues ◽  
...  
Keyword(s):  
Time Resolution ◽  
Detection Efficiency ◽  
High Time ◽  
High Time Resolution ◽  
Single Photons

High-time-resolution PM2.5 source apportionment based on multi-model with organic tracers in Beijing during haze episodes

2021 ◽  
Vol 772 ◽  
pp. 144766
Author(s):  
Lingling Lv ◽  
Yingjun Chen ◽  
Yong Han ◽  
Min Cui ◽  
Peng Wei ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Time Resolution ◽  
High Time ◽  
High Time Resolution
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