Chang Yang, Jiaxu Yue, Hongming Yang, Zhaoguo He, Fuliang Xiao, Sai Zhang, Yihua He, Si Liu, Qinghua Zhou, Zhonglei Gao, Yuyue Jin, Hui Zhao, Archie James Johnston
{"title":"Contribution of EMIC and Chorus Waves to the Formation of the Three-Belt of Ultra-Relativistic Electrons","authors":"Chang Yang, Jiaxu Yue, Hongming Yang, Zhaoguo He, Fuliang Xiao, Sai Zhang, Yihua He, Si Liu, Qinghua Zhou, Zhonglei Gao, Yuyue Jin, Hui Zhao, Archie James Johnston","doi":"10.1029/2024JA033380","DOIUrl":null,"url":null,"abstract":"<p>The Earth's radiation belts are usually composed of an inner and an outer zone. Previous studies have reported a third belt of ultra-relativistic electrons, but the mechanism requires to be further clarified. Here we report a very interesting feature of <span></span><math>\n <semantics>\n <mrow>\n <mn>3.4</mn>\n <mo>−</mo>\n <mn>6.3</mn>\n </mrow>\n <annotation> $3.4-6.3$</annotation>\n </semantics></math> MeV electrons during two storms in October 2018. During the October 7 storm the electrons in the region <span></span><math>\n <semantics>\n <mrow>\n <mi>L</mi>\n <mo>≈</mo>\n <mn>3.5</mn>\n <mo>−</mo>\n <mn>5.0</mn>\n </mrow>\n <annotation> $L\\approx 3.5-5.0$</annotation>\n </semantics></math> were quickly scattered by EMIC waves, leading to a storage ring left between <span></span><math>\n <semantics>\n <mrow>\n <mi>L</mi>\n <mo>≈</mo>\n <mn>3.0</mn>\n <mo>−</mo>\n <mn>3.5</mn>\n </mrow>\n <annotation> $L\\approx 3.0-3.5$</annotation>\n </semantics></math>. Over the following days, due to the chorus-driven acceleration, electron fluxes significantly increased in the region <span></span><math>\n <semantics>\n <mrow>\n <mi>L</mi>\n <mo>></mo>\n <mn>4</mn>\n </mrow>\n <annotation> $L > 4$</annotation>\n </semantics></math>, consequently allowing for a three-belt structure. During the October 13 storm the electrons in the region <span></span><math>\n <semantics>\n <mrow>\n <mi>L</mi>\n <mo>></mo>\n <mn>5</mn>\n </mrow>\n <annotation> $L > 5$</annotation>\n </semantics></math> were swept away by EMIC waves, leaving a narrow outer radiation belt confined within the region <span></span><math>\n <semantics>\n <mrow>\n <mi>L</mi>\n <mo>≈</mo>\n <mn>4</mn>\n <mo>−</mo>\n <mn>5</mn>\n </mrow>\n <annotation> $L\\approx 4-5$</annotation>\n </semantics></math> for several days. Numerical calculations demonstrate that the EMIC-driven loss and chorus-induced acceleration can account for the formation and evolution of the third-belt morphology.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"129 12","pages":""},"PeriodicalIF":2.6000,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Geophysical Research: Space Physics","FirstCategoryId":"89","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1029/2024JA033380","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
The Earth's radiation belts are usually composed of an inner and an outer zone. Previous studies have reported a third belt of ultra-relativistic electrons, but the mechanism requires to be further clarified. Here we report a very interesting feature of MeV electrons during two storms in October 2018. During the October 7 storm the electrons in the region were quickly scattered by EMIC waves, leading to a storage ring left between . Over the following days, due to the chorus-driven acceleration, electron fluxes significantly increased in the region , consequently allowing for a three-belt structure. During the October 13 storm the electrons in the region were swept away by EMIC waves, leaving a narrow outer radiation belt confined within the region for several days. Numerical calculations demonstrate that the EMIC-driven loss and chorus-induced acceleration can account for the formation and evolution of the third-belt morphology.