Characteristics and Geoeffectiveness of Small-scale Magnetic Flux Ropes in the Solar Wind
Magnetic flux ropes, often observed during intervals of interplanetary coronal mass ejections, have long been recognized to be critical in space weather. In this work, we focus on magnetic flux rope structure but on a much smaller scale, and not necessarily related to interplanetary coronal mass eje...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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The Korean Space Science Society
2017-12-01
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| Series: | Journal of Astronomy and Space Sciences |
| Subjects: | |
| Online Access: | http://ocean.kisti.re.kr/downfile/volume/kosss/OJOOBS/2017/v34n4/OJOOBS_2017_v34n4_237.pdf |
| _version_ | 1827361208758435840 |
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| author | Myeong Joon Kim Kyung Sun Park Dae-Young Lee Cheong-Rim Choi Rok Soon Kim Kyungsuk Cho Kyu-Cheol Choi Jaehun Kim |
| author_facet | Myeong Joon Kim Kyung Sun Park Dae-Young Lee Cheong-Rim Choi Rok Soon Kim Kyungsuk Cho Kyu-Cheol Choi Jaehun Kim |
| author_sort | Myeong Joon Kim |
| collection | DOAJ |
| description | Magnetic flux ropes, often observed during intervals of interplanetary coronal mass ejections, have long been recognized to be critical in space weather. In this work, we focus on magnetic flux rope structure but on a much smaller scale, and not necessarily related to interplanetary coronal mass ejections. Using near-Earth solar wind advanced composition explorer (ACE) observations from 1998 to 2016, we identified a total of 309 small-scale magnetic flux ropes (SMFRs). We compared the characteristics of identified SMFR events with those of normal magnetic cloud (MC) events available from the existing literature. First, most of the MCs and SMFRs have similar values of accompanying solar wind speed and proton densities. However, the average magnetic field intensity of SMFRs is weaker (~7.4 nT) than that of MCs (~10.6 nT). Also, the average duration time and expansion speed of SMFRs are ~2.5 hr and 2.6 km/s, respectively, both of which are smaller by a factor of ~10 than those of MCs. In addition, we examined the geoeffectiveness of SMFR events by checking their correlation with magnetic storms and substorms. Based on the criteria Sym-H < -50 nT (for identification of storm occurrence) and AL < -200 nT (for identification of substorm occurrence), we found that for 88 SMFR events (corresponding to 28.5 % of the total SMFR events), substorms occurred after the impact of SMFRs, implying a possible triggering of substorms by SMFRs. In contrast, we found only two SMFRs that triggered storms. We emphasize that, based on a much larger database than used in previous studies, all these previously known features are now firmly confirmed by the current work. Accordingly, the results emphasize the significance of SMFRs from the viewpoint of possible triggering of substorms. |
| first_indexed | 2024-03-08T06:59:46Z |
| format | Article |
| id | doaj.art-60540eb06f244a4194c14117097b780f |
| institution | Directory Open Access Journal |
| issn | 2093-5587 2093-1409 |
| language | English |
| last_indexed | 2024-03-08T06:59:46Z |
| publishDate | 2017-12-01 |
| publisher | The Korean Space Science Society |
| record_format | Article |
| series | Journal of Astronomy and Space Sciences |
| spelling | doaj.art-60540eb06f244a4194c14117097b780f2024-02-03T06:06:05ZengThe Korean Space Science SocietyJournal of Astronomy and Space Sciences2093-55872093-14092017-12-0134423724410.5140/JASS.2017.34.4.237Characteristics and Geoeffectiveness of Small-scale Magnetic Flux Ropes in the Solar WindMyeong Joon Kim0Kyung Sun Park1Dae-Young Lee2Cheong-Rim Choi3Rok Soon Kim4Kyungsuk Cho5Kyu-Cheol Choi6Jaehun Kim7Department of Astronomy and Space Science, Chungbuk National University, Cheongju 28644, KoreaDepartment of Astronomy and Space Science, Chungbuk National University, Cheongju 28644, KoreaDepartment of Astronomy and Space Science, Chungbuk National University, Cheongju 28644, KoreaDepartment of Astronomy and Space Science, Chungbuk National University, Cheongju 28644, KoreaKorea Astronomy and Space Science Institute, Daejeon 34055, KoreaKorea Astronomy and Space Science Institute, Daejeon 34055, KoreaSELab, Inc., Seoul 06049, KoreaThe Korean Space Weather Center of National Radio Research Agency, Jeju 63025, KoreaMagnetic flux ropes, often observed during intervals of interplanetary coronal mass ejections, have long been recognized to be critical in space weather. In this work, we focus on magnetic flux rope structure but on a much smaller scale, and not necessarily related to interplanetary coronal mass ejections. Using near-Earth solar wind advanced composition explorer (ACE) observations from 1998 to 2016, we identified a total of 309 small-scale magnetic flux ropes (SMFRs). We compared the characteristics of identified SMFR events with those of normal magnetic cloud (MC) events available from the existing literature. First, most of the MCs and SMFRs have similar values of accompanying solar wind speed and proton densities. However, the average magnetic field intensity of SMFRs is weaker (~7.4 nT) than that of MCs (~10.6 nT). Also, the average duration time and expansion speed of SMFRs are ~2.5 hr and 2.6 km/s, respectively, both of which are smaller by a factor of ~10 than those of MCs. In addition, we examined the geoeffectiveness of SMFR events by checking their correlation with magnetic storms and substorms. Based on the criteria Sym-H < -50 nT (for identification of storm occurrence) and AL < -200 nT (for identification of substorm occurrence), we found that for 88 SMFR events (corresponding to 28.5 % of the total SMFR events), substorms occurred after the impact of SMFRs, implying a possible triggering of substorms by SMFRs. In contrast, we found only two SMFRs that triggered storms. We emphasize that, based on a much larger database than used in previous studies, all these previously known features are now firmly confirmed by the current work. Accordingly, the results emphasize the significance of SMFRs from the viewpoint of possible triggering of substorms.http://ocean.kisti.re.kr/downfile/volume/kosss/OJOOBS/2017/v34n4/OJOOBS_2017_v34n4_237.pdfmagnetic flux ropemagnetic cloudsolar wind |
| spellingShingle | Myeong Joon Kim Kyung Sun Park Dae-Young Lee Cheong-Rim Choi Rok Soon Kim Kyungsuk Cho Kyu-Cheol Choi Jaehun Kim Characteristics and Geoeffectiveness of Small-scale Magnetic Flux Ropes in the Solar Wind Journal of Astronomy and Space Sciences magnetic flux rope magnetic cloud solar wind |
| title | Characteristics and Geoeffectiveness of Small-scale Magnetic Flux Ropes in the Solar Wind |
| title_full | Characteristics and Geoeffectiveness of Small-scale Magnetic Flux Ropes in the Solar Wind |
| title_fullStr | Characteristics and Geoeffectiveness of Small-scale Magnetic Flux Ropes in the Solar Wind |
| title_full_unstemmed | Characteristics and Geoeffectiveness of Small-scale Magnetic Flux Ropes in the Solar Wind |
| title_short | Characteristics and Geoeffectiveness of Small-scale Magnetic Flux Ropes in the Solar Wind |
| title_sort | characteristics and geoeffectiveness of small scale magnetic flux ropes in the solar wind |
| topic | magnetic flux rope magnetic cloud solar wind |
| url | http://ocean.kisti.re.kr/downfile/volume/kosss/OJOOBS/2017/v34n4/OJOOBS_2017_v34n4_237.pdf |
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