Sains Malaysiana 47(3)(2018): 595–601

http://dx.doi.org/10.17576/jsm-2018-4703-21

 

Pemerhatian Arus Ionosfera semasa Suar Suria Kuat Menggunakan Data Magnetometer Dasar

(Observation of Ionospheric Current during Strong Solar Flare Using Ground Based Magnetometer)

 

N.M.N. ANNADURAI¹, N.S.A. HAMID^1* & A. YOSHIKAWA^2,3

 

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: 16 October 2017

 

ABSTRAK

Suar suria merujuk kepada aktiviti matahari yang ditafsirkan sebagai cahaya terang yang meletus secara tiba-tiba dari permukaan matahari. Ia mampu menjejaskan sistem ionosfera bumi justeru mengganggu mana-mana arus yang mengalir di lapisan tersebut. Kejadian ini dapat diperhatikan melalui pemerhatian data magnetometer yang dicerap di bumi. Kesan umum suar suria adalah peningkatan kekonduksian ionosfera seterusnya meningkatkan keamatan arus namun didapati terdapat beberapa suar suria mampu memberikan kesan sebaliknya. Terdapat kajian yang melaporkan bahawa satu suar suria mampu meningkatkan keamatan arus di sesetengah kawasan dan pengurangan keamatan pada kawasan yang lain. Kajian lepas pula lebih tertumpu kepada kesan suar suria pada kawasan sektor tertentu atau setempat. Walau bagaimanapun, kajian ini mengambil pendekatan untuk menganalisis sifat suar suria dan kesannya menggunakan taburan data yang lebih meluas iaitu melibatkan stesen magnetometer yang dipasang di lima sektor. Data yang digunakan adalah daripada jaringan Magnetic Data Acquisition System/Circum Pan Magnetometer Network Pacific (MAGDAS/CPMN) dan suar suria dikenal pasti melalui data fluks sinar-X yang dicerap daripada satelit Geostationary Operational Environmental Satellite 15 (GOES 15). Keputusan kajian menunjukkan kesan suar suria yang tidak pernah ditemui sebelum ini iaitu pengurangan keamatan arus pada semua data cerapan di khatulistiwa magnetik dan punca yang dicadangkan adalah kewujudan arus elektrojet berlawanan. Selain itu, keputusan kajian turut mendapati bahawa suar suria tersebut berlaku pada fasa pemulihan ribut geomagnet semasa soltis Jun dalam fasa suria menaik.

 

Kata kunci: Arus ionosfera; medan geomagnet; suar suria

 

ABSTRACT

Solar flare is referring to sun's activity define as sudden intense bright light coming from its surface. It can immediately affect earth's ionosphere system thus perturb any currents flowing in the layer. The activity can be monitored using ground based magnetometer data. Regularly, the event will enhance the ionospheric conductivity thus increase the magnitude of the currents however the opposite effect has been reported recently. There were studies reported that a solar flare is capable to increase current intensity at some location and reduces it at other location. Previous study were focused on solar flare effect at some particular area sector or locally. Therefore, our approach is to analyze solar flare feature and its effect using extensive magnetometer data distribution which involve stations from five sectors. Data are obtained from Magnetic Data Acquisition System/Circum-pan Pacific Magnetometer Network (MAGDAS/CPMN) and solar flare is identified using Geostationary Operational Environmental Satellite 15 (GOES 15) X-ray flux data. Our study discovered a new effect of solar flare which is reduction of current intensity at all magnetic equator data and the proposed factor is existence of counter electrojet current. Apart from that, we also found that this solar flare occurred on geomagnetic storm recovery phase during June solstice in inclining phase of solar cycle.

 

Keywords: Geomagnetic field; ionospheric current; solar flare

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*Corresponding author; email: shazana.ukm@gmail.com