Magnetic latitude and local time distributions of ionospheric currents during a geomagnetic storm

2012 ◽  
Vol 117 (A7) ◽  
pp. n/a-n/a ◽  
Author(s):  
Yuji Tsuji ◽  
Atsuki Shinbori ◽  
Takashi Kikuchi ◽  
Tsutomu Nagatsuma
Keyword(s):  
Geomagnetic Storm ◽  
Local Time ◽  
Ionospheric Currents ◽  
Magnetic Latitude

scholarly journals The effects of neutral inertia on ionospheric currents in the high-latitude thermosphere following a geomagnetic storm

1993 ◽  
Vol 98 (A5) ◽  
pp. 7775-7790 ◽  
Author(s):  
W. Deng ◽  
T. L. Killeen ◽  
A. G. Burns ◽  
R. G. Roble ◽  
J. A. Slavin ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
High Latitude ◽  
Ionospheric Currents

scholarly journals Topside equatorial zonal ion velocities measured by C/NOFS during rising solar activity

2014 ◽  
Vol 32 (2) ◽  
pp. 69-75 ◽  
Author(s):  
W. R. Coley ◽  
R. A. Stoneback ◽  
R. A. Heelis ◽  
M. R. Hairston
Keyword(s):  
Solar Activity ◽  
Local Time ◽  
Geomagnetic Field ◽  
General Pattern ◽  
Magnetic Latitude ◽  
Ion Drifts ◽  
F Region ◽  
Westerly Flow ◽  
Solar Local Time ◽  
Ion Velocity

Abstract. The Ion Velocity Meter (IVM), a part of the Coupled Ion Neutral Dynamic Investigation (CINDI) instrument package on the Communication/Navigation Outage Forecast System (C/NOFS) spacecraft, has made over 5 yr of in situ measurements of plasma temperatures, composition, densities, and velocities in the 400–850 km altitude range of the equatorial ionosphere. These measured ion velocities are then transformed into a coordinate system with components parallel and perpendicular to the geomagnetic field allowing us to examine the zonal (horizontal and perpendicular to the geomagnetic field) component of plasma motion over the 2009–2012 interval. The general pattern of local time variation of the equatorial zonal ion velocity is well established as westward during the day and eastward during the night, with the larger nighttime velocities leading to a net ionospheric superrotation. Since the C/NOFS launch in April 2008, F10.7 cm radio fluxes have gradually increased from around 70 sfu to levels in the 130–150 sfu range. The comprehensive coverage of C/NOFS over the low-latitude ionosphere allows us to examine variations of the topside zonal ion velocity over a wide level of solar activity as well as the dependence of the zonal velocity on apex altitude (magnetic latitude), longitude, and solar local time. It was found that the zonal ion drifts show longitude dependence with the largest net eastward values in the American sector. The pre-midnight zonal drifts show definite solar activity (F10.7) dependence. The daytime drifts have a lower dependence on F10.7. The apex altitude (magnetic latitude) variations indicate a more westerly flow at higher altitudes. There is often a net topside subrotation at low F10.7 levels, perhaps indicative of a suppressed F region dynamo due to low field line-integrated conductivity and a low F region altitude at solar minimum.

scholarly journals A study of geomagnetic field variations along the 80° S geomagnetic parallel

2017 ◽  
Vol 35 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Stefania Lepidi ◽  
Lili Cafarella ◽  
Patrizia Francia ◽  
Andrea Piancatelli ◽  
Manuela Pietrolungo ◽  
...  
Keyword(s):  
Local Time ◽  
Geomagnetic Field ◽  
Daily Variation ◽  
Low Frequency ◽  
Magnetic Local Time ◽  
The Other ◽  
Ionospheric Currents ◽  
Wave Propagation Direction ◽  
Predominant Effect ◽  
Local Noon

Abstract. The availability of measurements of the geomagnetic field variations in Antarctica at three sites along the 80° S geomagnetic parallel, separated by approximately 1 h in magnetic local time, allows us to study the longitudinal dependence of the observed variations. In particular, using 1 min data from Mario Zucchelli Station, Scott Base and Talos Dome, a temporary installation during 2007–2008 Antarctic campaign, we investigated the diurnal variation and the low-frequency fluctuations (approximately in the Pc5 range, ∼ 1–7 mHz). We found that the daily variation is clearly ordered by local time, suggesting a predominant effect of the polar extension of midlatitude ionospheric currents. On the other hand, the pulsation power is dependent on magnetic local time maximizing around magnetic local noon, when the stations are closer to the polar cusp, while the highest coherence between pairs of stations is observed in the magnetic local nighttime sector. The wave propagation direction observed during selected events, one around local magnetic noon and the other around local magnetic midnight, is consistent with a solar-wind-driven source in the daytime and with substorm-associated processes in the nighttime.

Location in magnetic latitude and local time of the tropical ultraviolet bands seen from Apollo 16

1973 ◽  
Vol 35 (10) ◽  
pp. 1905-IN3 ◽  
Author(s):  
B.A Tinsley ◽  
A.B Christensen ◽  
Jane M Broadt ◽  
C.L Hammond
Keyword(s):  
Local Time ◽  
Magnetic Latitude

scholarly journals Morphology in the total electron content under geomagnetic disturbed conditions: results from global ionosphere maps

2007 ◽  
Vol 25 (7) ◽  
pp. 1555-1568 ◽  
Author(s):  
Zhao Biqiang ◽  
Wan Weixing ◽  
Liu Libo ◽  
Mao Tian
Keyword(s):  
Geomagnetic Storm ◽  
Local Time ◽  
Statistical Study ◽  
Electron Content ◽  
Geomagnetic Disturbances ◽  
Total Electron ◽  
Summer Hemisphere ◽  
Storm Effect ◽  
Time Variations ◽  
Winter Hemisphere

Abstract. Using 8-year global ionosphere maps (GIMs) of TEC products from the Jet Propulsion Laboratory (JPL), we make a statistical study on the morphology of the global ionospheric behaviors with respect to the geomagnetic disturbances. Results show that the behaviors of TEC during geomagnetic storm present clear seasonal and local time variations under geomagnetic control in a similar way as those of NmF2 (Field and Rishbeth, 1997). A negative phase of TEC occurs with high probability in the summer hemisphere and most prominent near the geomagnetic poles, while a positive phase is obvious in the winter hemisphere and in the far pole region. A negative storm effect toward lower latitudes tends to occur from post-midnight to the morning sector and recedes to high latitude in the afternoon. A positive storm effect is separated by geomagnetic latitudes and magnetic local time. Furthermore, ionospheric responses at different local time sectors with respect to the storm commencement shows very different developing processes corresponding to the evolution of the geomagnetic storm. A daytime positive storm effect is shown to be more prominent in the American region than those in the Asian and European regions, which may suggest a longitudinal effect of the ionospheric storm.

Magnetic latitude and local time dependence of the amplitude of geomagnetic sudden commencements

2009 ◽  
Vol 114 (A4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Atsuki Shinbori ◽  
Yuji Tsuji ◽  
Takashi Kikuchi ◽  
Tohru Araki ◽  
Shinichi Watari
Keyword(s):  
Time Dependence ◽  
Local Time ◽  
Magnetic Latitude ◽  
Sudden Commencements ◽  
Local Time Dependence

scholarly journals Nighttime Magnetic Perturbation Events Observed in Arctic Canada: 3. Occurrence and Amplitude as Functions of Magnetic Latitude, Local Time, and Magnetic Disturbance Indices

Space Weather ◽  
2021 ◽  
Vol 19 (3) ◽  
Author(s):  
Mark J. Engebretson ◽  
Viacheslav A. Pilipenko ◽  
Erik S. Steinmetz ◽  
Mark B. Moldwin ◽  
Martin G. Connors ◽  
...  
Keyword(s):  
Local Time ◽  
Magnetic Disturbance ◽  
Arctic Canada ◽  
Magnetic Perturbation ◽  
Magnetic Latitude

scholarly journals Magnetic storm-induced enhancement in neutral composition at low latitudes as inferred by O(<sup>1</sup>D) dayglow measurements from Chile

2004 ◽  
Vol 22 (9) ◽  
pp. 3241-3250 ◽  
Author(s):  
D. Pallamraju ◽  
S. Chakrabarti ◽  
C. E. Valladares
Keyword(s):  
Gravity Wave ◽  
Magnetic Storm ◽  
Geomagnetic Storm ◽  
Local Time ◽  
Direct Effect ◽  
Spatial Structures ◽  
Low Latitude ◽  
Equatorial Ionization Anomaly ◽  
Low Latitudes ◽  
Spread F

Abstract. We describe the effect of the 6 November 2001 magnetic storm on the low latitude thermospheric composition. Daytime red line (OI 630.0nm) emissions from Carmen Alto, Chile showed anomalous 2-3 times larger emissions in the morning (05:30-08:30 Local Time; LT) on the disturbed day compared to the quiet days. We interpret these emission enhancements to be caused due to the increase in neutral densities over low latitudes, as a direct effect of the geomagnetic storm. As an aftereffect of the geomagnetic storm, the dayglow emissions on the following day show gravity wave features that gradually increase in periodicities from around 30min in the morning to around 100min by the evening. The integrated dayglow emissions on quiet days show day-to-day variabilities in spatial structures in terms of their movement away from the magnetic equator in response to the Equatorial Ionization Anomaly (EIA) development in the daytime. The EIA signatures in the daytime OI 630.0nm column-integrated dayglow emission brightness show different behavior on days with and without the post-sunset Equatorial Spread F (ESF) occurrence.

scholarly journals April 2000 geomagnetic storm: ionospheric drivers of large geomagnetically induced currents

2003 ◽  
Vol 21 (3) ◽  
pp. 709-717 ◽  
Author(s):  
A. Pulkkinen ◽  
A. Thomson ◽  
E. Clarke ◽  
A. McKay
Keyword(s):  
Geomagnetic Storm ◽  
Large Scale ◽  
Regional Scale ◽  
Normal Operation ◽  
Technological Systems ◽  
Geomagnetically Induced Currents ◽  
Ionospheric Currents ◽  
Ionospheric Current ◽  
Induced Currents ◽  
Current Systems

Abstract. Geomagnetically induced currents (GIC) flowing in technological systems on the ground are a direct manifestation of space weather. Due to the proximity of very dynamic ionospheric current systems, GIC are of special interest at high latitudes, where they have been known to cause problems, for example, for normal operation of power transmission systems and buried pipelines. The basic physics underlying GIC, i.e. the magnetosphere – ionosphere interaction and electromagnetic induction in the ground, is already quite well known. However, no detailed study of the drivers of GIC has been carried out and little is known about the relative importance of different types of ionospheric current systems in terms of large GIC. In this study, the geomagnetic storm of 6–7 April 2000 is investigated. During this event, large GIC were measured in technological systems, both in Finland and in Great Britain. Therefore, this provides a basis for a detailed GIC study over a relatively large regional scale. By using GIC data and corresponding geomagnetic data from north European magnetometer networks, the ionospheric drivers of large GIC during the event were identified and analysed. Although most of the peak GIC during the storm were clearly related to substorm intensifications, there were no common characteristics discernible in substorm behaviour that could be associated with all the GIC peaks. For example, both very localized ionospheric currents structures, as well as relatively large-scale propagating structures were observed during the peaks in GIC. Only during the storm sudden commencement at the beginning of the event were large-scale GIC evident across northern Europe with coherent behaviour. The typical duration of peaks in GIC was also quite short, varying between 2–15 min.Key words. Geomagnetism and paleo-magnetism (geomagnetic induction) – Ionosphere (ionospheric disturbances) – Magnetospheric physics (storms and substorms)

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