scholarly journals Diurnal UT Variation of low Latitude Geomagnetic Storms Using six Indices

2021 ◽  
Author(s):  
N. Balan ◽  
S. Tulasi Ram ◽  
V. Manu ◽  
Lingxin Zhao ◽  
Zan‐Yang Xing ◽  
...  
Keyword(s):  
Geomagnetic Storms ◽  
Low Latitude

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.

Equatorial and low-latitude ionospheric TEC response to CIR-driven geomagnetic storms at different longitude sectors

2020 ◽  
Vol 66 (8) ◽  
pp. 1947-1966 ◽  
Author(s):  
Teshome Dugassa ◽  
John Bosco Habarulema ◽  
Melessew Nigussie
Keyword(s):  
Geomagnetic Storms ◽  
Low Latitude

scholarly journals A case-study of the low-latitude thermosphere during geomagnetic storms and its new representation by improved MSIS model

1998 ◽  
Vol 16 (11) ◽  
pp. 1513-1518 ◽  
Author(s):  
T. K. Pant ◽  
R. Sridharan
Keyword(s):  
Geomagnetic Storms ◽  
Correction Term ◽  
Atmospheric Model ◽  
Simple Relation ◽  
Rate Of Change ◽  
Low Latitude ◽  
Model Predictions ◽  
The Difference ◽  
Almost All

Abstract. The thermospheric temperatures from low and equatorial latitudes during geomagnetically disturbed periods are known to exhibit significant deviations from atmospheric model predictions. Also, the oscillatory features seen in the observations are not accounted for by the models. A simple relation has been established between the difference in the observed and model-predicted temperatures and the rate of change of Dst, the magnetic index representing the ring current variabilities. Using this relation, a correction term has been added to the latest MSIS-90 model algorithm and almost all the observed variations in neutral temperatures spectroscopically determined from Mt.Abu, a low-latitude station in India, are successfully reproduced for two moderate geomagnetic storms.Key words. Low-latitude thermosphere · MSIS model · Stormtime model predictions · FP spectroscopic temperatures  

Theoretically modeling the low-latitude, ionospheric response to large geomagnetic storms

Radio Science ◽  
2006 ◽  
Vol 41 (5) ◽  
Author(s):  
D. Anderson ◽  
A. Anghel ◽  
E. Araujo ◽  
V. Eccles ◽  
C. Valladares ◽  
...  
Keyword(s):  
Geomagnetic Storms ◽  
Low Latitude ◽  
Ionospheric Response

Anomalous enhancement in daytime 40-kHz signal amplitude accompanied by geomagnetic storms, earthquakes and meteor showers

1995 ◽  
Vol 13 (10) ◽  
pp. 1117-1123 ◽  
Author(s):  
B. K. De ◽  
S. K. Sarkar
Keyword(s):  
Geomagnetic Storms ◽  
Signal Strength ◽  
Signal Amplitude ◽  
Meteor Showers ◽  
Night Time ◽  
Low Latitude ◽  
After Effects ◽  
D Region

Abstract. Anomalous propagational characteristics, daytime signal levels greater than night-time, were observed. The amplitude records of a 40-kHz signal propagated over a distance of 5100 km from Sanwa, Japan to Calcutta along a low-latitude path show higher signal strength at midday compared to the midnight level on days preceded by principal geomagnetic storms, earthquakes and major meteor showers. This is explained by the increased ionization in the D-region following geophysical events. The storm after-effects only have a duration of a single day in this low-latitude path.

scholarly journals The HIA instrument on board the Tan Ce 1 Double Star near-equatorial spacecraft and its first results

2005 ◽  
Vol 23 (8) ◽  
pp. 2757-2774 ◽  
Author(s):  
H. Rème ◽  
I. Dandouras ◽  
C. Aoustin ◽  
J. M. Bosqued ◽  
J. A. Sauvaud ◽  
...  
Keyword(s):  
Solar Wind ◽  
Ring Current ◽  
Geomagnetic Storms ◽  
Distribution Functions ◽  
Double Star ◽  
Magnetospheric Substorms ◽  
Scientific Cooperation ◽  
Low Latitude ◽  
First Results ◽  
Academy Of Sciences

Abstract. On 29 December 2003, the Chinese spacecraft Tan Ce 1 (TC-1), the first component of the Double Star mission, was successfully launched within a low-latitude eccentric orbit. In the framework of the scientific cooperation between the Academy of Sciences of China and ESA, several European instruments, identical to those developed for the Cluster spacecraft, were installed on board this spacecraft. The HIA (Hot Ion Analyzer) instrument on board the TC-1 spacecraft is an ion spectrometer nearly identical to the HIA sensor of the CIS instrument on board the 4 Cluster spacecraft. This instrument has been specially adapted for TC-1. It measures the 3-D distribution functions of the ions between 5 eV/q and 32 keV/q without mass discrimination. TC-1 is like a fifth Cluster spacecraft to study the interaction of the solar wind with the magnetosphere and to study geomagnetic storms and magnetospheric substorms in the near equatorial plane. HIA was commissioned in February 2004. Due to the 2 RE higher apogee than expected, some in-flight improvements were needed in order to use HIA in the solar wind in the initial phase of the mission. Since this period HIA has obtained very good measurements in the solar wind, the magnetosheath, the dayside and nightside plasma sheet, the ring current and the radiation belts. We present here the first results in the different regions of the magnetosphere and in the solar wind. Some of them are very new and include, for example, ion dispersion structures in the bow shock and ion beams close to the magnetopause. The huge interest in the orbit of TC-1 is strongly demonstrated.

scholarly journals Analysis of Geomagnetic Storms Using Wavelet Transforms

2017 ◽  
Vol 4 (1) ◽  
pp. 119 ◽  
Author(s):  
B. Adhikari ◽  
R. Khatiwada ◽  
N. P. Chapagain
Keyword(s):  
Magnetic Field ◽  
Wavelet Analysis ◽  
Interplanetary Magnetic Field ◽  
High Frequency ◽  
Wavelet Transforms ◽  
Geomagnetic Storms ◽  
Wavelet Coefficient ◽  
Low Latitude ◽  
Statistical Tool ◽  
Sheath Region

<p class="Default">Geomagnetic storms are recognized as a worldwide decrease of the horizontal component of the Earth’s magnetic field measured at middle- and low-latitude magnetometers. The variations in the geomagnetic field during geomagnetic storms can be reproduced by changes in the interplanetary magnetic field and the solar wind velocity. Wavelet analysis, a useful statistical tool for analyzing variability has been used for this study. Wavelet transforms seem to be suited to analyze short-lived high-frequency phenomena such as discontinuities (shocks) in signals and transient structures. Wavelet analysis employed in the present work helps to decompose the time series of scales of interplanetary magnetic field (IMF-Bz) into different scales. To identify geomagnetic storms, the equatorial index, SYM-H has been used. The increase of wavelet coefficient amplitudes of the IMF-Bz is well correlated with the arrival of the shock and sheath region</p><p><strong>Journal of Nepal Physical Society</strong><em><br /></em>Volume 4, Issue 1, February 2017: 119-124</p>

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