scholarly journals Modulation of equatorial electrojet plasma waves by overshielding electric field during geomagnetic storms

2011 ◽  
Vol 116 (A8) ◽  
pp. n/a-n/a ◽  
Author(s):  
E. B. Shume ◽  
E. R. de Paula ◽  
M. A. Abdu
Keyword(s):  
Electric Field ◽  
Geomagnetic Storms ◽  
Equatorial Electrojet ◽  
Plasma Waves

scholarly journals ANALISIS PENGARUH PENETRASI MEDAN LISTRIK LINTANG TINGGI KE LINTANG RENDAH TERHADAP IONOSFER SAAT BADAI GEOMAGNET (ANALYSIS OF THE ELECTRIC FIELD PENETRATION EFFECT FROM HIGH TO LOW LATITUDES ON THE IONOSPHERE DURING GEOMAGNETIC STORM)

2018 ◽  
Vol 14 (2) ◽  
pp. 97
Author(s):  
Anwar Santoso ◽  
Dadang Nurmali ◽  
Mira Juangsih ◽  
Iyus Edi Rusnadi ◽  
Sri Ekawati ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Current ◽  
High Latitude ◽  
Delay Time ◽  
Geomagnetic Storms ◽  
Equatorial Electrojet ◽  
Minimum Point ◽  
Low Latitude ◽  
Dst Index ◽  
Low Latitudes

The influence of geomagnetic storms on the ionosphere in the equatorial and low latitudes can be either rising or falling value of the value foF2 with the different response delay time. The difference in response is one of them allegedly influenced by the modification of Equatorial Electrojet (EEJ) generated by the penetration of high latitude electric field towards the low latitude electric field and the equator. Therefore, this paper analyzes the influence of the high latitude penetration of electric current to the low latitude electric current towards the ionosphere response to Indonesia's current geomagnetic storms using the data foF2 BPAA Sumedang (SMD; 6,910 S; 106,830E geographic coordinates or 16,550 S; 179,950 E magnetic coordinates) and data from the Biak geomagnetic field station (BIK; 1,080 S; 136,050 E geographic coordinates or  9,730 S; 207,390 E magnetic coordinates) in 2000-2001. The result showed that the injection of the electric field of the high latitudes to lower latitudes causing foF2 BPAA Sumedang to be disturbed. Onset of the foF2 disturbance in BPAA Sumedang started coincide with EEJ(HBIK-HDRW) and reached its minimum point with a time delay between 0 to 4 hours before and after Dst index reached the minimum point. For a delay time of 0 to 4 hours after the Dst index reached the minimum point, the results were in accordance with the research results from the prior research. However, for the time difference of between 0 to 4 hours before the Dst index reached the minimum point, the results differ from their results. AbstrakPengaruh badai geomagnet terhadap ionosfer di ekuator dan lintang rendah berupa naiknya nilai foF2 atau turunnya nilai foF2 dengan waktu tunda respon berbeda-beda. Perbedaan respon tersebut salah satunya diduga dipengaruhi oleh modifikasi Equatorial electrojet (EEJ) yang dihasilkan oleh penetrasi medan listrik lintang tinggi sampai daerah lintang rendah dan ekuator. Oleh karena itu, dalam makalah ini dilakukan analisis pengaruh penetrasi arus listrik lintang tinggi ke lintang rendah terhadap ionosfer saat badai geomagnet menggunakan data foF2 dari Balai Pengamatan Antariksa dan Atmosfer (BPAA) Sumedang (SMD; 6,910 LS; 106,830 BT koordinat geografis atau 16,550 LS; 179,950 BT koordinat magnet) dan data medan geomagnet dari stasiun Biak (BIK; 1,080 LS; 136,050 BT koordinat geografis atau 9,730 LS; 207,390 BT koordinat magnet) tahun 2000-2001. Hasilnya diperoleh bahwa penetrasi medan listrik dari lintang tinggi ke lintang lebih rendah Indonesia menyebabkan foF2 BPAA Sumedang terganggu. Onset gangguan foF2 BPAA Sumedang mulai terjadi bertepatan dengan EEJ(HBIK-HDRW) mencapai titik minimumnya dengan jeda waktu antara 0 sampai 4 jam sebelum dan sesudah indeks Dst mencapai minimum. Untuk beda waktu 0 sampai 4 jam sesudah indeks Dst mencapai minimum, hasilnya bersesuaian dengan hasil penelitian peneliti sebelumnya. Namun, untuk beda waktu 0 sampai 4 jam sebelum indeks Dst mencapai minimum, hasilnya merupakan temuan berbeda dari hasil mereka.

scholarly journals Imaging radar observations and nonlocal theory of large-scale plasma waves in the equatorial electrojet

2002 ◽  
Vol 20 (8) ◽  
pp. 1167-1179 ◽  
Author(s):  
D. L. Hysell ◽  
J. L. Chau
Keyword(s):  
Large Scale ◽  
Equatorial Electrojet ◽  
Plasma Waves ◽  
Radar Data ◽  
Nonlocal Theory ◽  
Main Beam ◽  
Night Time ◽  
Plasma Irregularities ◽  
Background Density ◽  
Spontaneous Regeneration

Abstract. Large-scale (l ~ 1 km) waves in the daytime and night-time equatorial electrojet are studied using coherent scatter radar data from Jicamarca. Images of plasma irregularities within the main beam of the radar are formed using interferometry with multiple baselines. These images are analyzed according to nonlocal gradient drift instability theory and are also compared to nonlinear computer simulations carried out recently by Ronchi et al. (1991) and Hu and Bhattacharjee (1999). In the daytime, the large-scale waves assume a non-steady dynamical equilibrium state characterized by the straining and destruction of the waves by shear and diffusion followed by spontaneous regeneration as predicted by Ronchi et al. (1991). At night, when steep plasma density gradients emerge, slowly propagating large-scale vertically extended waves predominate. Eikonal analysis suggests that these waves are trapped (absolutely unstable) or are nearly trapped (convectively unstable) and are able to tunnel between altitude regions which are locally unstable. Intermediate-scale waves are mainly transient (convectively stable) but can become absolutely unstable in narrow altitude bands determined by the background density profile. These characteristics are mainly consistent with the simulations presented by Hu and Bhattacharjee (1999). A new class of large-scale primary waves is found to occur along bands that sweep westward and downward from high altitudes through the E-region at twilight.Key words. Ionosphere (equatorial ionosphere; ionospheric irregularities; plasma waves and instabilities)

Resonant Microwave Absorption in an Overdense Plasma Column

1980 ◽  
Vol 35 (3) ◽  
pp. 293-301
Author(s):  
G. Böhm
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Plasma Column ◽  
Plasma Waves ◽  
Coupling Mechanism ◽  
Resonant Coupling ◽  
Overdense Plasma ◽  
Full Absorption ◽  
High Electric Field Strength

Abstract A resonant coupling mechanism is presented which leads to nearly full absorption of an electromagnetic wave in an overdense plasma column. In the resonance case a strong enhancement of the electric field strength within the plasma is found. Under certain conditions this high electric field strength causes parametric excitation of plasma waves in the underdense edges of the discharge. It turned out that the occurance of this decay process is mainly determined by the density gradients in the plasma.

Coupled plasma waves in a system of two two-dimensional superlattices in the presence of a quantizing electric field

2013 ◽  
Vol 47 (10) ◽  
pp. 1312-1315
Author(s):  
S. Yu. Glazov ◽  
E. S. Kubrakova ◽  
N. E. Mescheryakova
Keyword(s):  
Electric Field ◽  
Plasma Waves ◽  
Two Dimensional

scholarly journals On the origin of pre-reversal enhancement of the zonal equatorial electric field

2009 ◽  
Vol 27 (5) ◽  
pp. 2053-2056 ◽  
Author(s):  
M. C. Kelley ◽  
R. R. Ilma ◽  
G. Crowley
Keyword(s):  
Electric Field ◽  
Equatorial Electrojet ◽  
Neutral Wind ◽  
Radio Observatory ◽  
Dominant Mechanism ◽  
Partial Closure ◽  
Incoherent Scatter ◽  
Unique Event ◽  
The Earth ◽  
Dusk Sector

Abstract. In November 2004, a large and variable interplanetary electric field (IEF) was felt in the reference frame of the Earth. This electric field penetrated to the magnetic equator and, when the Jicamarca Radio Observatory (JRO) was in the dusk sector, resulted in a reversal of the normal zonal component of the field. In turn, this caused a counter-electrojet (CEJ), a westward current rather than the usual eastward current. At the time of the normal pre-reversal enhancement (PRE) of the eastward field, the Jicamarca incoherent scatter radar (ISR) observed that the westward component became even more westward. Two of the three current explanations for the PRE depend on the neutral wind patterns. However, this unique event was such that the neutral wind-driven dynamos could not have changed. The implication is that the Haerendel-Eccles mechanism, which involves partial closure of the equatorial electrojet (EEJ) after sunset, must be the dominant mechanism for the PRE.

scholarly journals Estimation of interplanetary electric field conditions for historical geomagnetic storms

2015 ◽  
Vol 120 (9) ◽  
pp. 7307-7317 ◽  
Author(s):  
Sandeep Kumar ◽  
B. Veenadhari ◽  
S. Tulasi Ram ◽  
R. Selvakumaran ◽  
Shyamoli Mukherjee ◽  
...  
Keyword(s):  
Electric Field ◽  
Geomagnetic Storms ◽  
Field Conditions
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