Signatures of 2-day wave in the E-region electric fields and their relationship to winds and ionospheric currents

Abstract. We analyze the effects of the 2-day wave activity in the EEJ using one coherent scatter radar and eight magnetometer stations located close to the dip equator. The wavelet analysis of the magnetometer data reveals a 2-day signature in the semidiurnal geomagnetic tide. The E-region zonal background ionospheric electric field, derived from coherent radar measurements, shows 2-day oscillations in agreement with such oscillations in the magnetometers data. An anticorrelation between the amplitude of the tidal periodicites (diurnal and semidiurnal) and that of the 2-day signature is also shown in the electric fields. The results are compared with simultaneous observations of 2-day planetary wave in meridional winds and ionosonde data. Further, our results are discussed based on the analysis of the magnetic activity.

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Influence of uncertainties of the empirical models for inferring the E-region electric fields at the dip equator

Earth Planets and Space ◽

10.1186/s40623-016-0479-0 ◽

2016 ◽

Vol 68 (1) ◽

Cited By ~ 8

Author(s):

Juliano Moro ◽

Clezio Marcos Denardini ◽

Laysa Cristina Araújo Resende ◽

Sony Su Chen ◽

Nelson Jorge Schuch

Keyword(s):

Electric Fields ◽

Empirical Models ◽

E Region ◽

Dip Equator

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E region electric fields at the dip equator and anomalous conductivity effects

Advances in Space Research ◽

10.1016/j.asr.2012.06.003 ◽

2013 ◽

Vol 51 (10) ◽

pp. 1857-1869 ◽

Cited By ~ 7

Author(s):

C.M. Denardini ◽

H.C. Aveiro ◽

J.H.A. Sobral ◽

J.V. Bageston ◽

L.M. Guizelli ◽

...

Keyword(s):

Electric Fields ◽

E Region ◽

Dip Equator

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

Annales Geophysicae ◽

10.1007/s00585-000-0099-6 ◽

2000 ◽

Vol 18 (1) ◽

pp. 99-110 ◽

Cited By ~ 14

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)

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Penetration of the electric fields of the geomagnetic sudden commencement over the globe as observed with the HF Doppler sounders and magnetometers

Earth Planets and Space ◽

10.1186/s40623-020-01350-8 ◽

2021 ◽

Vol 73 (1) ◽

Author(s):

Takashi Kikuchi ◽

Jaroslav Chum ◽

Ichiro Tomizawa ◽

Kumiko K. Hashimoto ◽

Keisuke Hosokawa ◽

...

Keyword(s):

Electric Field ◽

Electric Fields ◽

Sudden Commencement ◽

Ionospheric Currents ◽

Republic Of China ◽

F Region ◽

Electric And Magnetic Fields ◽

Magnetometer Data ◽

Electric Potentials ◽

Geomagnetic Sudden Commencement

AbstractUsing the HF Doppler sounders at middle and low latitudes (Prague, Czech Republic; Tucuman, Argentina; Zhongli, Republic of China, and Sugadaira, Japan), we observed the electric fields of the geomagnetic sudden commencement (SC) propagating near-instantaneously (within 10 s) over the globe. We found that the electric fields of the preliminary impulse (PI) and main impulse (MI) of the SC are in opposite direction to each other and that the PI and MI electric fields are directed from the dusk to dawn and dawn to dusk, respectively, manifesting the nature of the curl-free potential electric field. We further found that the onset and peak of the PI electric field are simultaneous on the day and nightsides (0545, 1250, 1345 MLT) within the resolution of 10 s. With the magnetometer data, we confirmed the near-instantaneous development of the ionospheric currents from high latitudes to the equator and estimated the location of the field-aligned currents that supply the ionospheric currents. The global simultaneity of the electric and magnetic fields does not require the contribution of the magnetohydrodynamic waves in the magnetosphere nor in the F-region ionosphere. The global simultaneity and day–night asymmetry of the electric fields are explained with the ionospheric electric potentials transmitted at the speed of light by the TM0 mode waves in the Earth-ionosphere waveguide.

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Role of inductive electric fields and currents in dynamical ionospheric situations

Annales Geophysicae ◽

10.5194/angeo-25-437-2007 ◽

2007 ◽

Vol 25 (2) ◽

pp. 437-455 ◽

Cited By ~ 14

Author(s):

H. Vanhamäki ◽

O. Amm ◽

A. Viljanen

Keyword(s):

Electric Field ◽

Electric Fields ◽

Temporal Variations ◽

Ionospheric Currents ◽

Calculation Technique ◽

Induced Field ◽

Ionospheric Electric Field ◽

Electric Fields And Currents ◽

Current Systems

Abstract. We study the role of ionospheric induction in different commonly observed ionospheric situations. These include an intensifying electrojet, westward travelling surge (WTS) and Ω-band. We use data based, realistic models for these phenomena and calculate the inductive electric fields that are created due to the temporal variations of ionospheric currents. The ionospheric induction problem is solved using a new calculation technique that can handle non-uniform, time-dependent conductances and electric fields of any geometry. We find that in some situations inductive effects are not negligible and the ionospheric electric field is not a pure potential field, but has a significant induced rotational part. In the WTS and Ω-band models the induced electric field is concentrated in a small area, where the time derivatives are largest. In the electrojet model the induced field is significant over a large part of the jet area. In these examples the induced electric field has typical values of few mV/m, which amounts to several tens of percents of the potential electric field present at the same locations. The induced electric field is associated with ionospheric and field aligned currents (FAC), that modify the overall structure of the current systems. Especially the induced FAC are often comparable to the non-inductive FAC, and may thus modify the coupling between the ionosphere and magnetosphere in the most dynamical situations. We also present some examples with very simple ionospheric current systems, where the effect of different ionospheric parameters on the induction process is studied.

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Equatorial E region electric fields at the dip equator: 1. Variabilities in eastern Brazil and Peru

Journal of Geophysical Research Space Physics ◽

10.1002/2016ja022751 ◽

2016 ◽

Vol 121 (10) ◽

pp. 10,220-10,230 ◽

Cited By ~ 4

Author(s):

J. Moro ◽

C. M. Denardini ◽

L. C. A. Resende ◽

S. S. Chen ◽

N. J. Schuch

Keyword(s):

Electric Fields ◽

Eastern Brazil ◽

E Region ◽

Dip Equator

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Velocities of auroral coherent echoes at 12 and 144 MHz

Annales Geophysicae ◽

10.5194/angeo-20-1647-2002 ◽

2002 ◽

Vol 20 (10) ◽

pp. 1647-1661 ◽

Cited By ~ 7

Author(s):

A. V. Koustov ◽

D. W. Danskin ◽

M. V. Uspensky ◽

T. Ogawa ◽

P. Janhunen ◽

...

Keyword(s):

Electric Field ◽

Plasma Waves ◽

Auroral Ionosphere ◽

F Region ◽

Radar Systems ◽

Radar Echoes ◽

E Region ◽

Ionospheric Electric Field ◽

Coherent Radar ◽

Eiscat Measurements

Abstract. Two Doppler coherent radar systems are currently working at Hankasalmi, Finland, the STARE and CUTLASS radars operating at ~144 MHz and ~12 MHz, respectively. The STARE beam 3 is nearly co-located with the CUTLASS beam 5, providing an opportunity for echo velocity comparison along the same direction but at significantly different radar frequencies. In this study we consider an event when STARE radar echoes are detected at the same ranges as CUT-LASS radar echoes. The observations are complemented by EISCAT measurements of the ionospheric electric field and electron density behaviour at one range of 900 km. Two separate situations are studied; for the first one, CUTLASS observed F-region echoes (including the range of the EIS-CAT measurements), while for the second one CUTLASS observed E-region echoes. In both cases STARE E-region measurements were available. We show that F-region CUT-LASS velocities agree well with the convection component along the CUTLASS radar beam, while STARE velocities are typically smaller by a factor of 2–3. For the second case, STARE velocities are found to be either smaller or larger than CUTLASS velocities, depending on the range. Plasma physics of E-and F-region irregularities is discussed in attempt to explain the inferred relationship between various velocities. Special attention is paid to ionospheric refraction that is important for the detection of 12-MHz echoes.Key words. Ionosphere (ionospheric irregularities; plasma waves and instabilities; auroral ionosphere)

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Midday reversal of equatorial ionospheric electric field

Annales Geophysicae ◽

10.1007/s00585-997-1309-2 ◽

1997 ◽

Vol 15 (10) ◽

pp. 1309-1315 ◽

Cited By ~ 16

Author(s):

R. G. Rastogi

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Electric Field ◽

Electric Fields ◽

Ring Current ◽

Geomagnetic Storms ◽

Low Latitude ◽

E Region ◽

Sporadic E ◽

Ionospheric Electric Field

Abstract. A comparative study of the geomagnetic and ionospheric data at equatorial and low-latitude stations in India over the 20 year period 1956–1975 is described. The reversal of the electric field in the ionosphere over the magnetic equator during the midday hours indicated by the disappearance of the equatorial sporadic E region echoes on the ionograms is a rare phenomenon occurring on about 1% of time. Most of these events are associated with geomagnetically active periods. By comparing the simultaneous geomagnetic H field at Kodaikanal and at Alibag during the geomagnetic storms it is shown that ring current decreases are observed at both stations. However, an additional westward electric field is superimposed in the ionosphere during the main phase of the storm which can be strong enough to temporarily reverse the normally eastward electric field in the dayside ionosphere. It is suggested that these electric fields associated with the V×Bz electric fields originate at the magnetopause due to the interaction of the solar wind and the interplanetary magnetic field.

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