The Solar Wind Density Control on the Prompt Penetration Electric Field and Equatorial Electrojet

2020 ◽  
Vol 125 (9) ◽  
Author(s):  
B. Nilam ◽  
S. Tulasi Ram ◽  
K. Shiokawa ◽  
N. Balan ◽  
Q. Zhang
Keyword(s):  
Solar Wind ◽  
Electric Field ◽  
Equatorial Electrojet ◽  
Solar Wind Density ◽  
Density Control ◽  
Prompt Penetration Electric Field

scholarly journals An evidence for prompt electric field disturbance driven by changes in the solar wind density under northward IMF Bz condition

2016 ◽  
Vol 121 (5) ◽  
pp. 4800-4810 ◽  
Author(s):  
Diptiranjan Rout ◽  
D. Chakrabarty ◽  
R. Sekar ◽  
G. D. Reeves ◽  
J. M. Ruohoniemi ◽  
...  
Keyword(s):  
Solar Wind ◽  
Electric Field ◽  
Solar Wind Density ◽  
Field Disturbance

scholarly journals Signatures of Sudden Storm Commencement on the equatorial thermospheric dayglow

2019 ◽  
Vol 9 ◽  
pp. A31
Author(s):  
Sukumarn N.G.K. Sumod ◽  
Tarun K. Pant ◽  
Asokan P. Ajesh
Keyword(s):  
Solar Wind ◽  
Electric Field ◽  
Sudden Increase ◽  
Abrupt Increase ◽  
Equatorial Station ◽  
Compression Phase ◽  
F Region ◽  
Ram Pressure ◽  
Airglow Emissions ◽  
Prompt Penetration Electric Field

It has been observed that the OI 630.0 nm dayglow emission over a dip equatorial station, Trivandrum (8.5° N, 77° E, dip 0.5° N), India registered an abrupt increase of ~ 2000 R during the compression phase of the magnetosphere as dictated by a sudden increase in solar wind ram pressure. Furthermore, an unusual depletion of these emissions has been observed during the eastward interplanetary electric field (IEF), concomitant with southward excursion of IMF Bz. The ionosonde and magnetometer observations confirmed the effects of prompt penetration electric field (PPEF). Associated with the eastward PPEF, formation of F3 layers were also noticed. These unique results, which emphasize the effect of Sudden Storm Commencement/IEF on these equatorial daytime airglow emissions are discussed in context of changes in the equatorial zonal electric field and F region height variations associated with polar/auroral activities due to the magnetosphere-ionosphere coupling.

scholarly journals Observations of polar patches generated by solar wind Alfvén wave coupling to the dayside magnetosphere

1999 ◽  
Vol 17 (4) ◽  
pp. 463-489 ◽  
Author(s):  
P. Prikryl ◽  
J. W. MacDougall ◽  
I. F. Grant ◽  
D. P. Steele ◽  
G. J. Sofko ◽  
...  
Keyword(s):  
Solar Wind ◽  
Electric Field ◽  
Alfven Waves ◽  
Alfven Wave ◽  
Alfvén Waves ◽  
Convection Cell ◽  
Convection Flow ◽  
Vhf Radar ◽  
Sky Imager ◽  
The Imf

Abstract. A long series of polar patches was observed by ionosondes and an all-sky imager during a disturbed period (Kp = 7- and IMF Bz < 0). The ionosondes measured electron densities of up to 9 × 1011 m-3 in the patch center, an increase above the density minimum between patches by a factor of \\sim4.5. Bands of F-region irregularities generated at the equatorward edge of the patches were tracked by HF radars. The backscatter bands were swept northward and eastward across the polar cap in a fan-like formation as the afternoon convection cell expanded due to the IMF By > 0. Near the north magnetic pole, an all-sky imager observed the 630-nm emission patches of a distinctly band-like shape drifting northeastward to eastward. The 630-nm emission patches were associated with the density patches and backscatter bands. The patches originated in, or near, the cusp footprint where they were formed by convection bursts (flow channel events, FCEs) structuring the solar EUV-produced photoionization and the particle-produced auroral/cusp ionization by segmenting it into elongated patches. Just equatorward of the cusp footprint Pc5 field line resonances (FLRs) were observed by magnetometers, riometers and VHF/HF radars. The AC electric field associated with the FLRs resulted in a poleward-progressing zonal flow pattern and backscatter bands. The VHF radar Doppler spectra indicated the presence of steep electron density gradients which, through the gradient drift instability, can lead to the generation of the ionospheric irregularities found in patches. The FLRs and FCEs were associated with poleward-progressing DPY currents (Hall currents modulated by the IMF By) and riometer absorption enhancements. The temporal and spatial characteristics of the VHF backscatter and associated riometer absorptions closely resembled those of poleward moving auroral forms (PMAFs). In the solar wind, IMP 8 observed large amplitude Alfvén waves that were correlated with Pc5 pulsations observed by the ground magnetometers, riometers and radars. It is concluded that the FLRs and FCEs that produced patches were driven by solar wind Alfvén waves coupling to the dayside magnetosphere. During a period of southward IMF the dawn-dusk electric field associated with the Alfvén waves modulated the subsolar magnetic reconnection into pulses that resulted in convection flow bursts mapping to the ionospheric footprint of the cusp.Key words. Ionosphere (polar ionosphere). Magneto- spheric physics (magnetosphere-ionosphere interactions; polar wind-magnetosphere interactions).

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