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Sains Malaysiana 47(8)(2018): 1923–1929 http://dx.doi.org/10.17576/jsm-2018-4708-34
Perubahan
Sistem Arus Ionosfera di Kawasan Asia Tenggara semasa Ribut Geomagnet pada Fasa
Suria Minimum
(Changes
in Ionospheric Currents System at Southeast Asia Region during
Geomagnetic Storm in Solar's Minimum Phase)
NURUL SHAZANA ABDUL HAMID1*, VIKSUTHORN AI WEN1, NUR IZZATI MOHD ROSLI1 & AKIMASA YOSHIKAWA2,3
1Pusat Pengajian Fizik
Gunaan, Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia, 43600 UKM
Bangi, Selangor Darul Ehsan, Malaysia
2Department of Earth
and Planetary Sciences, Faculty of Sciences, 33 Kyushu University, 6-10-1
Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
3International Center
for Space Weather Science and Education (ICSWSE), Kyushu University, 53
6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
Received:
3 August 2017/Accepted: 19 March 2018
ABSTRAK
Sistem arus di ionosfera khatulistiwa terdiri daripada
elektrojet khatulistiwa (EEJ) dan suria senyap (Sq). Arus EEJ merupakan satu jalur arus
yang mengalir ke arah timur sepanjang kawasan dip khatulistiwa.
Arus Sq pula adalah gegelung arus yang mengalir di hemisfera utara
dan selatan bumi pada arah yang bertentangan. Kajian
ini bertujuan untuk menganalisis kesan aktiviti matahari terhadap
profil latitud sistem arus, khususnya di kawasan Asia Tenggara.
Data yang digunakan dalam kajian ini merangkumi data geomagnet
daripada lima stesen magnetometer dalam rangkaian MAGDAS iaitu stesen Muntinlupa
(MUT),
Cebu (CEB), Davao (DAV), Manado (MND)
dan Pare Pare (PRP). Keamatan arus EEJ yang
paling tinggi adalah pada waktu tengah hari sekitar 1000 dan
1100 LT
semasa solar minimum dan kajian ini telah menganalisis
sistem arus daripada 1000 hingga 1400 LT. Analisis menunjukkan
bahawa ribut geomagnet yang berlaku pada 23 April 2008 adalah
disebabkan oleh letusan jirim korona (CME)
yang memberikan peningkatan kepada nilai arus pada hari tersebut.
Peningkatan yang ketara dapat dilihat pada arus di stesen hemisfera
selatan, iaitu stesen MND dan PRP.
Berdasarkan analisis yang dilakukan, ia
turut mendapati bahawa ribut geomagnet memberikan peningkatan
kepada nilai arus walaupun di luar waktu puncak. Selain
itu, profil arus ini turut dibandingkan dengan profil arus pada
hari senyap iaitu pada 21 April 2008.
Kata kunci: Aktiviti matahari; EEJ;
sistem arus ionosfera; Sq
ABSTRACT
Equatorial ionospheric current system consists of equatorial
electrojet (EEJ) and solar quiet (Sq). EEJ current
is a ribbon of current flowing eastwards along the dip equator region. On the
other hand, Sq current is a loop of current that flows at the Earth’s northern
and southern hemispheres in different directions. This study is focusing on
analysing the effects of a solar event on the latitudinal profile of the
current system, specifically in Southeast Asian region. Data used in this study
are geomagnetic data from five magnetometer stations in MAGDAS network
which are Muntinlupa (MUT), Cebu (CEB),
Davao (DAV), Manado (MND) and Pare Pare (PRP).
The EEJ current intensity is known to be highest around noon
time between 1000 and 1100 LT during solar minimum and thus this
study analyses the current system from 1000 to 1400 LT.
The analysis showed that the geomagnetic storm occurred on 23 April 2008, which
is caused by coronal mass ejection (CME), gives rises to the
currents on that day. This increment is clearly observed on the currents at the
southern hemisphere stations, which are MND and PRP.
Our analysis also found that this geomagnetic storm gives increment to the
current at the non-peak time. Apart from that, the current profile on this day
is compared with the current profile from a quiet day on 21 April 2008.
Keywords: EEJ;
ionospheric current system; solar event; Sq
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*Corresponding author; email: shazana.ukm@gmail.com
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