Umfaniswano omkhulu we-aurora owabonwa phansi ngobusuku bukaKhisimusi ka-2022 uqinisekisiwe ukuthi i-polar rain aurora. Lona bekuwumbono wokuqala osekelwe phansi we-polar rain aurora. Ngokungafani ne-aurora evamile eshayelwa ama-electron esigameko agcinwe ku-magnetotail we-magnetosphere yomhlaba, i-polar rain aurora yenziwa ama-electron ahamba ngokuqondile esuka e-solar corona eya ezindaweni ezipholile zomhlaba ngemigqa evulekile yamagnetic field ukuze ifinyelele umvuthwandaba "polar imvula” imvula ye-electron ebangela ukukhishwa kwe-optical lapho ihlangana ne-oxygen nama-athomu e-nitrogen emkhathini.
Indaba ye-aurorae, ukukhanya okukhazimulayo okumibalabala kuyakhombisa (okubizwa ngokuthi izibani zaseNyakatho noma i-aurora borealis esifundeni sesigxobo esisenyakatho kanye ne-Southern Lights noma i-Aurora Australis esifundeni sesigxobo esiseningizimu) iqala kungqimba lwe-coronal yomkhathi welanga. Izinga lokushisa lalesi singqimba somkhathi welanga liphezulu kakhulu. Ngenkathi izinga lokushisa le ungqimba lwe-photosphere (okuthathwa njengobuso belanga ngoba lokhu sikubona ngokukhanya) cishe ku-6000 Kelvin, izinga lokushisa elijwayelekile le-corona liphakathi kwesigidi esi-1 kuya kwezi-2 ze-Kelvin ngenxa 'ye-Coronal Heating Paradox'. Izinga lokushisa eliphakeme kangaka lenza i-corona ibe ungqimba lwe-plasma eshisa kakhulu. Umoya welanga ohlanganisa izinhlayiya ezinamandla kakhulu zikagesi (njengama-electron, ama-proton, izinhlayiya ze-alpha nama-ion asindayo) uqhubeka uphuma kungqimba lwe-coronal kuzo zonke izinhlangothi kuhlanganise nokuya ngaseMhlabeni.
Uhambo lwangaphandle lwezinhlayiya ezigcwele amandla ukusuka elangeni ukuya emhlabeni alulula futhi aluqondile. Ngokuvamile, izinhlayiya ze-ionized ziphambukiswa amandla kazibuthe omhlaba (magnetosphere) ngaleyo ndlela izinhlobo zokuphila nezinhlelo zikagesi emhlabeni zihlala zingathinteki emiphumeleni eyingozi yomoya welanga.
Kodwa-ke, uma kwenzeka ukukhishwa okukhulu kwezinhlayiya ezikhokhiswayo ezivela elangeni njengasendabeni ye-Coronal Mass Ejection (CMEs), i-magnetosphere yomhlaba iba namandla futhi imiphumela yesiphepho kazibuthe. Isiphepho sigcizelela i-magnetosphere size sibuyele emuva sijikijela ezinye zezinhlayiya ezikhokhisiwe ngaseMhlabeni.
Ibhendi ehlehlisayo yenkundla kazibuthe ihudula ama-electron emoyeni welanga phansi iye ezindaweni ezipholile lapho i-aurorae ibonwa khona ku-100-300 km ngaphezu kobuso emkhathini ongaphezulu. Umnikelo wama-proton namanye ama-ion emoyeni welanga ekwakhekeni kwe-aurora awunaki.
I-Aurora ngokuyisisekelo iwukuphuma kwamehlo okuphuma kuma-athomu komoyampilo kanye ne-nitrogen ajatshuliswa ama-electron anamandla ageleza esuka kuzibuthe eduze kwemigqa yomhlaba kazibuthe evaliwe (imvula ye-electron enamandla noma i-EEP ibhekisela ekufakweni kwamandla ama-electron emkhathini). Ukusebenzisana kwama-electron anamandla anomoya-mpilo osemkhathini kubangela imibala eluhlaza nebomvu kuyilapho ukusebenzisana ne-nitrogen kuholela ekukhiqizweni kwemibala eluhlaza okwesibhakabhaka nokubomvu.
Ngakho-ke, ukwakheka kwe-aurora kuqhutshwa ama-electron esigameko agcinwe ku-magnetotail (isifunda se-magnetosphere yomhlaba esikhukhulwa umoya welanga sibe umsila omkhulu ohlangothini olukude nelanga). Ama-electron agcinwe ku-magnetosphere athola amandla ngokuphoqelelwa komoya welanga abese eshona emkhathini ngokuqhuma ezindaweni ezipholile ukuze kubangele i-aurora.
Imvula yasePolar Aurora
Kodwa-ke, kuyaqabukela, ama-aurorae akheke ama-electron ahamba ngokuqondile esuka e-solar corona eya ezindaweni ezipholile zomhlaba emigqeni evulekile yakazibuthe ukuze afinyelele umvuthwandaba “ngemvula eshisayo” yemvula yama-electron. Imvula ye-electron enjalo itholakala inamandla lapho ukuminyana komoya welanga kuphansi. Ukukhishwa kwe-optical okubangelwa ama-electron anjalo abuthakathaka futhi i-aurora eyakhiwe ibizwa ngokuthi "i-polar rain aurora".
I-polar rain aurorae iye yabonwa amasathelayithi izikhathi ezimbalwa emkhathini. Nokho, alikho icala elake latholwa yizikhungo ezisekelwe phansi.
Ngo-25th-26th Disemba 2022, i-atypical aurora yathwetshulwa amakhamera asekelwe phansi esifundeni sase-Artic lapho umoya welanga usucishe wanyamalala. I-aurora eyabonwa yayiyiyunifomu futhi inkulu ngosayizi. Akuzange kubonakale njenge-aurora evamile. I-polar cap aurora evamile wumbukiso wokukhanya ogqamile obonisa iphethini eguquguqukayo yezibani ezinjengothingo. Kungase kubonakale njengamakhethini, imisebe, ama-spiral, noma njengokucwebezela okushintshayo. Thetha aurora ibonakala njengohlamvu lwesiGreki i-theta (i-oval enomugqa onqamula phakathi nendawo) lapho ibhekwa phezulu ngamasathelayithi. I-Theta aurorae nayo ibizwa ngokuthi 'ama-transpolar arcs' ngenxa yokubukeka kwama-arcs amakhulu uma ebonwa phezulu. 'Ama-arcs aqondaniswe nelanga.' ama-arcs amancane futhi afiphele abonwa ezindaweni zokubuka ezisekelwe phansi. Umkhawulo owodwa wama-arc uqondiswe eLangeni yingakho ubizwa ngokuthi 'Ama-arcs aqondaniswe nelanga. '
I-aurora eyabonwa ngobusuku bukaKhisimusi ngo-2022 yayibushelelezi, isakazekile futhi inkulu ngosayizi. Yayingabukeki njenge-aurora evamile ngakho-ke kwakucatshangwa ukuthi i-polar rain aurora. Ukuqinisekisa lokhu, abacwaningi baphenye lokhu besebenzisa idatha esekwe kwisathelayithi nesekelwe phansi.
Izithombe zesathelayithi zibonise ukuthi isifunda se-polar cap sasingenalutho ngokuphelele ekuqaleni. I-polar cap yaqala ukugcwala i-aurora engabonakali kahle ngo-25th Disemba. Kamuva, cishe yonke isifunda se-polar cap ngokushesha sambozwa ukukhishwa kwegesi okunamandla kodwa okungahlelekile kahle. Lokhu kugcwalisa ngezinga elikhulu kwe-polar cap ngokusakazwa kwe-aurorae kwaqhubeka cishe amahora angama-28. Ukukhishwa okunamandla ngaphakathi kwekepisi ye-polar kwaqala ukufiphala ekuseni ngo-26th NgoDisemba futhi kungakapheli amahora ambalwa, isakhiwo se-aurora sase sibuyele ekusabalaliseni okujwayelekile futhi i-polar cap yayingenalutho futhi.
Imvula ye-electron yemvula empophoma ngokuvamile ivela ku-hemisphere eyodwa kuphela kuye ngokuthi i-interplanetary magnetic field (IMF) ikuphi. Izithombe zesathelayithi ngesikhathi esisodwa zibonise ukugcwaliswa okuphelele kwesivalo se-polar eNyakatho Nenkabazwe kuyilapho i-polar cap ye-Southern Hemisphere yayingenalutho. Lokhu kuqaphe i-interhemispheric asymmetry kanye nokuma okulindelekile kwe-IMF kuphakamise ngokuqinile ukuthi i-aurora enkulu etholwe ngaphakathi kwe-polar cap yaseNyakatho Nenkabazwe kwakuyi-polar rain aurora. I-interhemispheric asymmetry nayo yabonakala kudatha ye-electron. Futhi, ukuhlobana phakathi kwesikhathi sokunyamalala komoya welanga kanye nokugcwaliswa kwe-cap ye-polar kwakukuhle kakhulu.
Izilinganiso zamehlo ezivela endaweni esekwe phansi edolobheni lase-Artic eLongyearbyen ngomhlaka-25th -26th UDisemba wabonisa ukuthi ama-electron anamandla aphezulu (>1 keV) akha ingxenye eyinhloko yemvula yama-electron. Ukuthutheleka kwama-electron anamandla aphezulu kwabonwa yisathelayithi. Ngenxa yalokho, i-aurora yayibonakala phansi njengokukhishwa kwe-greenish egqamile.
Ocwaningweni lwangaphambilini, kwaboniswa ukuthi i-aurora yemvula eshisayo inyakaza ngokumelene nokushona kwelanga ngamamitha angu-150/sec. Endabeni ye-atypical aurora ebonwe ngobusuku bukaKhisimusi ka-2022, ukuhlaziywa kwedatha ye-optical ye-cross-sectional kubonise ukuthi i-aurora yanda ngendlela ephikisana nokushona kwelanga kodwa isivinini se-aurora njengoba sibhekwa phansi sasiphindwe kabili kuya kathathu ngokushesha.
Ngakho-ke, umfaniswano omkhulu we-aurora obonakala emhlabathini ngobusuku bukaKhisimusi ngo-2022 kwakuyi-aurora yemvula epholile. Lokhu bekuwukubuka kokuqala okusekelwe phansi kwe-polar rain aurora, isici esiyingqayizivele soxhumano oluyinkimbinkimbi lwe-Sun-Earth.
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References:
- Hosokawa, K. et al 2024. I-aurora enkulu kakhulu endaweni epholile ngosuku lapho umoya welanga ucishe wanyamalala. UKUTHUTHUKISWA KWESAYENSI. 21 Juni 2024. Vol 10, Issue 25. DOI: https://doi.org/10.1126/sciadv.adn5276
- SWPC, NOAA. I-Aurora. Itholakala ngo https://www.swpc.noaa.gov/phenomena/aurora
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