scholarly journals Interaction between direct penetration and disturbance dynamo electric fields in the storm-time equatorial ionosphere

2005 ◽  
Vol 32 (17) ◽  
Author(s):  
N. Maruyama ◽  
A. D. Richmond ◽  
T. J. Fuller-Rowell ◽  
M. V. Codrescu ◽  
S. Sazykin ◽  
...  
Keyword(s):  
Electric Fields ◽  
Equatorial Ionosphere ◽  
Direct Penetration

Solar cycle effects on the electric fields in the equatorial ionosphere

1977 ◽  
Vol 82 (32) ◽  
pp. 5257-5261 ◽  
Author(s):  
R. F. Woodman ◽  
R. G. Rastogi ◽  
C. Calderon
Keyword(s):  
Solar Cycle ◽  
Electric Fields ◽  
Equatorial Ionosphere

scholarly journals Effects of solar eclipse on the electrodynamical processes of the equatorial ionosphere: a case study during 11 August 1999 dusk time total solar eclipse over India

2002 ◽  
Vol 20 (12) ◽  
pp. 1977-1985 ◽  
Author(s):  
R. Sridharan ◽  
C. V. Devasia ◽  
N. Jyoti ◽  
Diwakar Tiwari ◽  
K. S. Viswanathan ◽  
...  
Keyword(s):  
Electric Fields ◽  
Solar Eclipse ◽  
Equatorial Ionosphere ◽  
Hf Radar ◽  
F Region ◽  
Large Enhancement ◽  
Temporal Structures ◽  
E Region ◽  
Field Lines ◽  
Electric Fields And Currents

Abstract. The effects on the electrodynamics of the equatorial E- and F-regions of the ionosphere, due to the occurrence of the solar eclipse during sunset hours on 11 August 1999, were investigated in a unique observational campaign involving ground based ionosondes, VHF and HF radars from the equatorial location of Trivandrum (8.5° N; 77° E; dip lat. 0.5° N), India. The study revealed the nature of changes brought about by the eclipse in the evening time E- and F-regions in terms of (i) the sudden intensification of a weak blanketing ES-layer and the associated large enhancement of the VHF backscattered returns, (ii) significant increase in h' F immediately following the eclipse and (iii) distinctly different spatial and temporal structures in the spread-F irregularity drift velocities as observed by the HF radar. The significantly large enhancement of the backscattered returns from the E-region coincident with the onset of the eclipse is attributed to the generation of steep electron density gradients associated with the blanketing ES , possibly triggered by the eclipse phenomena. The increase in F-region base height immediately after the eclipse is explained as due to the reduction in the conductivity of the conjugate E-region in the path of totality connected to the F-region over the equator along the magnetic field lines, and this, with the peculiar local and regional conditions, seems to have reduced the E-region loading of the F-region dynamo, resulting in a larger post sunset F-region height (h' F) rise. These aspects of E-and F-region behaviour on the eclipse day are discussed in relation to those observed on the control day.Key words. Ionosphere (electric fields and currents; equatorial ionosphere; ionospheric irregularities)

scholarly journals Role of the magnetospheric and ionospheric currents in the generation of the equatorial scintillations during geomagnetic storms

2004 ◽  
Vol 22 (9) ◽  
pp. 3195-3202 ◽  
Author(s):  
L. Z. Biktash
Keyword(s):  
Solar Wind ◽  
Electric Fields ◽  
Ring Current ◽  
Geomagnetic Storms ◽  
Equatorial Ionosphere ◽  
Experimental Investigations ◽  
Polar Regions ◽  
Ionospheric Currents ◽  
Geomagnetic Variations ◽  
Activity Effect

Abstract. The equatorial ionosphere parameters, Kp, Dst, AU and AL indices characterized contribution of different magnetospheric and ionospheric currents to the H-component of geomagnetic field are examined to test the geomagnetic activity effect on the generation of ionospheric irregularities producing VLF scintillations. According to the results of the current statistical studies, one can predict near 70% of scintillations from Aarons' criteria using the Dst index, which mainly depicts the magnetospheric ring current field. To amplify Aarons' criteria or to propose new criteria for predicting scintillation characteristics is the question. In the present phase of the experimental investigations of electron density irregularities in the ionosphere new ways are opened up because observations in the interaction between the solar wind - magnetosphere - ionosphere during magnetic storms have progressed greatly. According to present view, the intensity of the electric fields and currents at the polar regions, as well as the magnetospheric ring current intensity, are strongly dependent on the variations of the interplanetary magnetic field. The magnetospheric ring current cannot directly penetrate the equatorial ionosphere and because of this difficulties emerge in explaining its relation to scintillation activity. On the other hand, the equatorial scintillations can be observed in the absence of the magnetospheric ring current. It is shown that in addition to Aarons' criteria for the prediction of the ionospheric scintillations, models can be used to explain the relationship between the equatorial ionospheric parameters, h'F, foF2, and the equatorial geomagnetic variations with the polar ionosphere currents and the solar wind.

scholarly journals Effects of disturbed electric fields in the low‐latitude and equatorial ionosphere during the 2015 St. Patrick's Day storm

2016 ◽  
Vol 121 (9) ◽  
pp. 9111-9126 ◽  
Author(s):  
Jiawei Kuai ◽  
Libo Liu ◽  
Jing Liu ◽  
S. Sripathi ◽  
Biqiang Zhao ◽  
...  
Keyword(s):  
Electric Fields ◽  
Equatorial Ionosphere ◽  
Low Latitude

scholarly journals Penetration of the convection and overshielding electric fields to the equatorial ionosphere during a quasiperiodicDP2 geomagnetic fluctuation event

2010 ◽  
Vol 115 (A5) ◽  
pp. n/a-n/a ◽  
Author(s):  
T. Kikuchi ◽  
Y. Ebihara ◽  
K. K. Hashimoto ◽  
R. Kataoka ◽  
T. Hori ◽  
...  
Keyword(s):  
Electric Fields ◽  
Equatorial Ionosphere

Ionospheric dynamic and coupling processes during geomagnetic storms

2020 ◽  
Author(s):  
Chaosong Huang
Keyword(s):  
Electric Fields ◽  
Geomagnetic Storms ◽  
Equatorial Ionosphere ◽  
Ion Composition ◽  
Hemispheric Differences ◽  
Ion Density ◽  
Ion Drift ◽  
Low Latitudes ◽  
Coupling Processes ◽  
Ionospheric Dynamics

<p>Geomagnetic storms cause the largest disturbances in the ionosphere-thermosphere system. We use measurements with satellites and ground based radars to study storm-induced variations in ionospheric plasma drift, ion density, and ion composition at low latitudes. It is found that the storm-time change of ion drift velocity in the equatorial ionosphere can reach 200-300 m/s, the change of ion density can be one or two orders of magnitude, and the change of ion composition can be 50-80%. These extremely large changes in the ionosphere can last for several hours or even a few days during the main and recovery phases of magnetic storms. The longitudinal, latitudinal and hemispheric differences of storm-time ionospheric disturbances are analyzed from measurements of multiple satellites or radar chain. Very long, continuous penetration of interplanetary electric fields to the equatorial ionosphere for 6 or even 14 hours are observed, and the time when disturbance dynamo electric fields become dominant is identified. The interplay of penetration, shielding, and disturbance dynamo electric fields in the storm-time ionosphere will be addressed. Mechanisms responsible for storm-time ionospheric dynamics will be discussed.</p>

Westward Electric Fields in the Afternoon Equatorial Ionosphere During Geomagnetically Quiet Times

2020 ◽  
Vol 125 (12) ◽  
Author(s):  
Ruilong Zhang ◽  
Libo Liu ◽  
You Yu ◽  
Huijun Le ◽  
Yiding Chen
Keyword(s):  
Electric Fields ◽  
Equatorial Ionosphere
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