Sains Malaysiana 52(8)(2023): 2309-2322

http://doi.org/10.17576/jsm-2023-5208-11

Examining Solar Flare Effects on Earth's Ionosphere using Ground-Based Measurements

(Pengkajian Kesan Nyalaan Suria terhadap Ionosfera Bumi menggunakan Pengukuran Dasar)

NURUL SHAZANA ABDUL HAMID^1,2,*, RAJA ADIBAH RAJA HALIM¹, IDAHWATI SARUDIN³, AKIMASA YOSHIKAWA^4,5 & AKIKO FUJIMOTO⁶

¹Department of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

²Space Science Centre (ANGKASA), Institute of Climate Change, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia

³School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia

⁴Department of Earth and Planetary Sciences, Faculty of Sciences, 33 Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan

⁵International Research Center for Space and Planetary Environmental Science (i-SPES), Kyushu University, 819-0395 Fukuoka, Japan

⁶Department of Artificial Intelligence, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4, Kawazu, Iizuka, Fukuoka 820-8502, Japan

Diserahkan: 28 Januari 2023/Diterima: 2 Ogos 2023

Abstract

This study investigated the simultaneous effects of solar flares (SFs) on both the D and E layers of Earth's ionosphere. The analysis focused on the M and X-class SFs that occurred during the 24th solar cycle as these two classes of SFs are known to produce significant effects on Earth’s environment, particularly during the daytime period. The data utilized to detect the SF events in this study were ground-based magnetometer data from the equatorial regions. Effects of the selected SF events on the E layer were investigated based on the EUEL index constructed using the geomagnetic data. Meanwhile, the changes in the strength of radio VLF signals in the D ionospheric layer during the selected SF events were monitored using Sudden Ionospheric Disturbance (SID) data. Two case studies were performed which consisted of four SF events from a total of 23 events that were detected by geomagnetic data during the period of study. Further analysis on the selected SF events showed the common effects of SFs on the D layer, which is the increment on the VLF signal measured from the SID stations although a different response was detected in the EUEL index variations. This indicates that the VLF signal always shows an increment even though a decrement in the ionization of the E layer occurs as a result of the SF events. The difference in responses could be attributed to the distinct changes in electron density of both layers during the SF occurrence. Further studies are needed to elucidate the underlying mechanism responsible for this unique response, utilizing appropriate parameters such as total electron content, as well as the electron density data to thoroughly analyze the ionospheric response during SF events.

Keywords: EEJ current; geomagnetic field; SID; solar flare; VLF signal

Abstrak

Penyelidikan ini mengkaji kesan nyalaan suria (SF) secara serentak pada kedua-dua lapisan D dan E ionosfera Bumi. Analisis memfokuskan kepada SF kelas M dan X yang berlaku semasa kitaran suria ke-24 kerana kedua-dua kelas SF ini menghasilkan kesan yang ketara ke atas persekitaran Bumi, terutamanya pada waktu siang. Data yang digunakan untuk mengesan kejadian SF dalam kajian ini ialah data magnetometer cerapan dasar dari rantau-rantau khatulistiwa. Kesan kejadian SF yang dipilih pada lapisan E telah dikaji berdasarkan indeks EUEL yang dibina menggunakan data medan geomagnet tersebut. Sementara itu, data Gangguan Ionosfera Mendadak (SID) digunakan untuk memantau perubahan kekuatan isyarat radio VLF pada lapisan D ionosfera untuk kejadian SF yang terpilih. Dua kajian kes telah dilakukan yang terdiri daripada empat kejadian SF daripada 23 peristiwa yang dikesan oleh data geomagnet sepanjang tempoh kajian. Analisis lanjut mengenai kejadian SF terpilih telah memerhatikan kesan umum SF pada lapisan D iaitu kenaikan pada isyarat VLF yang diukur dari stesen SID walaupun tindak balas berbeza dikesan dalam variasi indeks EUEL. Ini menunjukkan bahawa isyarat VLF sentiasa menunjukkan kenaikan walaupun pengurangan dalam pengionan lapisan E terjadi kesan daripada kejadian SF. Perbezaan dalam tindak balas ini boleh disebabkan oleh perubahan yang berbeza dalam ketumpatan elektron pada kedua-dua lapisan semasa berlakunya kejadian SF. Kajian lanjut diperlukan untuk menerangkan mekanisme tindak balas unik ini dengan menggunakan parameter yang sesuai seperti jumlah kandungan elektron serta data ketumpatan elektron untuk menganalisis secara menyeluruh akan tindak balas ionosfera semasa kejadian SF.

Kata kunci: Arus EEJ; isyarat VLF; medan geomagnet; nyalaan suria; SID

RUJUKAN

Annadurai, N.M.N., Hamid, N.S.A. & Yoshikawa, A. 2019. Statistical study of equatorial geomagnetic crochets. AIP Conference Proceedings 2111(1): 030003.

Annadurai, N.M.N., Hamid, N.S.A., Yamazaki, Y. & Yoshikawa, A. 2018. Investigation of unusual solar flare effect on the global ionospheric current system. Journal of Geophysical Research: Space Physics123(10): 8599-8609.

Contreira, D.B., Rodrigues, F.S., Makita, K., Brum, C.G.M., Gonzalez, W., Trivedi, N.B., Da Silva, M.R. & Schuch, N.J. 2005. An experiment to study solar flare effects on radio-communication signals. Advances in Space Research 36(12): 2455-2459.

Curto, J.J., Marsal, S., Blanch, E. & Altadill, D. 2018. Analysis of the solar flare effects of 6 September 2017 in the ionosphere and in the earth’s magnetic field using spherical elementary current systems. Space Weather 16(11): 1709-1720.

Dahlgren, H., Sundberg, T., Collier, A.B., Koen, E. & Meyer, S. 2011. Solar flares detected by the new narrowband VLF receiver at SANAE IV. South African Journal of Science 107(9-10): 1-8.

Das, U., Pallamraju, D. & Chakrabarti, S. 2010. Effect of an x-class solar flare on OI 630nm dayglow emissions. Journal of Geophysical Research: Space Physics 115: A08302.

Deshpande, S.D., Subrahmanyam, C.V. & Mitra, A.P. 1972. Ionospheric effects of solar flares-I. The statistical relationship between X-ray flares and SID’s. Journal of Atmospheric and Terrestrial Physics 34(2): 211-227.

Grodji, O.D.F., Doumbia, V., Amaechi, P.O., Mazaudier, C.A., N’guessan, K., Diaby, K.A.A., Zie, T. & Boka, K. 2021. A study of solar flare effects on the geomagnetic field components during solar cycles 23 and 24. Journal of Atmosphere 13(1): 69.

Hamid, N.S.A., Rosli, N.I.M., Ismail, W.N.I. & Yoshikawa, A. 2021. Effects of solar activity on ionospheric current system in the Southeast Asia region. Indian Journal of Physics 95(4): 543-550.

Hamid, N.S.A., Liu, H., Uozumi, T. & Yumoto, K. 2013. Equatorial electrojet dependence on solar activity in the Southeast Asia sector. Antarctic Record 57: 329-337.

Ismail, W.N.I., Hamid, N.S.A., Abdullah, M., Yoshikawa, A., Uozumi, T. & Radzi, Z.M. 2021. Comparison of EEJ longitudinal variation from satellite and ground measurements over different solar activity levels. Universe 7(2): 23.

Kahler, S. 1992. Solar flares and coronal mass ejections. Annual Review of Astronomy and Astrophysics 30(1): 113-141.

Kumar, A. & Kumar, S. 2018. Solar flare effects on D-region ionosphere using VLF measurements during low- and high-solar activity phases of solar cycle 24. Earth Planets Space 70(1): 29.

Le, H., Liu, L., Chen, B., Lei, J., Yue, X. & Wan, W. 2007. Modeling the responses of the middle latitude ionosphere to solar flares. J. Atmos. Solar-Terr. Phys. 69: 1587-1598.

McRae, W.M. & Thomson, N.R. 2000. VLF phase and amplitude: daytime ionospheric parameters. J. Atmos. Solar-Terrestrial Phys. 62(7): 609-618.

Moral, A.C., Kalafatoglu Eyiguler, E.C. & Kaymaz, Z. 2013. Sudden ionospheric disturbances and their detection over Istanbul. 20136th International Conference on Recent Advances in Space Technologies (RAST). pp. 765-768.

Natras, R., Horozovic, D. & Mulic, M. 2018. Strong solar flare detection and its impact on ionospheric layers and on coordinates accuracy in the Western Balkans in October 2014. SN Applied Sciences 49: 2019.

Qian, L. & Woods, T.N. 2021. Solar flare effects on the thermosphere and ionosphere. In Upper Atmosphere Dynamics and Energetics, edited by Wang, W., Zhang, Y. & Paxton, L.J. American Geophysical Union. pp. 253-274.

Rosli, N.I.M., Hamid, N.S.A., Abdullah, M., Yusof, K.A., Yoshikawa, A., Uozumi, T. & Rabiu, B. 2022. The variation of counter-electrojet current at the southeast Asian sector during different solar activity levels. Applied Sciences 12(14): 7138.

Sengupta, P.R. 1980. Solar x-ray control of the D-region of the ionosphere. Journal of Atmospheric and Solar-Terrestrial Physics 42(4): 329-335.

Sengupta, P.R. 1970. X-ray control of the E-layer of the ionosphere. Journal of Atmospheric and Solar-Terrestrial Physics 32(7): 1273-1282.

Shah, R.A.R.H., Abdul Hamid, N.S. & Yoshikawa, A. 2021. Effect of strong solar flare events on the geomagnetic equatorial region during solar cycle-24. International Conference on Space Science and Communication, IconSpace. pp. 298-302.

Singh, A., Rao, S.S., Rathore, V.S., Singh, S.K. & Singh, A.K. 2020. Effect of intense solar flare on TEC variation at low-latitude station Varanasi. J. Astrophys. Astr. 41: 19.

Sripati, S., Balachandran, N., Veenadhari, B., Singh, R. & Emperumal, K. 2013. Response of the equatorial and low-latitude ionosphere to an intense X-class solar flare (X7/2B) as observed on 09 August 2011. Journal of Geophysical Research: Space Physics 118: 2648-2659.

Sumod, S.G. & Pant, T.K. 2019. An investigation of solar flare effects on equatorial ionosphere and thermosphere using co-ordinated measurements. Earth, Planets and Space 71: 125.

Ugwu, E.B.I., Okechukwu, U.D. & Udoka, A.J. 2021. On the effects of solar flare on geomagnetic components across all latitudes during solar minimum and maximum. Academic Journals: Scientific Research and Essays 16(3): 42-50.

Uozumi, T., Yumoto, K., Kitamura, K., Abe, S., Kakinami, Y., Shinohara, M., Yoshikawa, A., Kawano, H., Ueno, T., Tokunaga, T., Mcnamara, D., Ishituka, J.K., Dutra, S.L.G., Damtie, B., Doumbia, V., Obrou, O., Rabiu, A.B., Adimula, I.A., Othman, M., Fairos, M., Otadoy, R.E.S. & MAGDAS Group. 2008. A new index to monitor temporal and long-term variations of the equatorial electrojet by MAGDAS/CPMN real-time data: EE-Index. Earth Planets and Space 60: 785-790.

Yamazaki, Y., Yumoto, K., Yoshikawa, A., Watari, S. & Utada, H. 2009. Characteristics of counter-Sq SFE (SFE*) at the dip equator CPMN stations. Journal of Geophysical Research 114: A05306.

Zhang, L., Mursula, K., Usoskin, I. & Wang, H. 2011. Global analysis of active longitudes of solar x-ray flares. Journal of Atmospheric and Solar-Terrestrial Physics 73(2-3): 258-263.

Zhang, R., Liu, L., Le, H. & Chen, Y. 2017. Equatorial ionospheric electro-dynamics during solar flares. Geophysical Research Letters 44(10): 4558-4565.

*Pengarang untuk surat-menyurat; email: shazana.ukm@gmail.com