Source Altitudes and Heating Properties of Electron Conics Observed at High Altitudes by the Arase Satellite

Source Altitudes and Heating Properties of Electron Conics Observed at High Altitudes by the Arase Satellite | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Source Altitudes and Heating Properties of Electron Conics Observed at High Altitudes by the Arase Satellite Hiroki Ishimaru, Shun Imajo, Yoshizumi Miyoshi, Yoichi Kazama, and 15 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7635028/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 13 Mar, 2026 Read the published version in Earth, Planets and Space → Version 1 posted 5 You are reading this latest preprint version Abstract Electron conics are a distinct electron distribution observed in Earth's magnetosphere, characterized by enhanced fluxes of upgoing electrons at several keV, especially in the auroral acceleration region. This study utilizes high-altitude (27,000-32,000 km) observations made by the Arase satellite to investigate the characteristics of electron conics after they have passed through the heating region, employing the high angular resolution of its Low-Energy Particle experiments - electron analyzer (LEPe). We analyzed eight electron conic events between 2017 and 2022 to estimate their source altitudes using mirror ratios and potential differences and by comparing pre- and post-heating data to investigate heating properties. Our results show that the source region of conics has an upper boundary at 9,000-14,000 km, with the peak flux originating from a central altitude of 3,000-7,000 km. This region spatially coincides with the source of auroral kilometric radiation (AKR): the the central altitude of the source of conics corresponds to the lower boundary of the AKR source, suggesting that a longer residence time of particles within the wave field lead to stronger heating. The analysis revealed that upgoing conic electrons exhibit higher temperatures and lower densities. While their number flux is conserved, indicating the energization of a magnetospheric population, the energy flux is enhanced by a factor of up to four, a rate higher than that reported in previous studies. A test particle simulation, using observed plasma parameters and incorporating stochastic perpendicular heating, reproduces the main features of observed conics in terms of both energy and pitch angle. Our simulation shows that electron conics evolve into narrow, field-aligned beams at higher altitudes, suggesting that some of the anti-Earthward-flowing beams observed in the magnetotail may actually be unresolved conics. These findings contribute to the understanding of energy transport between the auroral acceleration region and the magnetotail and show the importance of high-resolution instrumentation. Electron conics Auroral acceleration region Arase satellite Electron heating Auroral kilometric radiation Wave-particle interactions Magnetosphere High-energy electrons Full Text Supplementary Files ga.png Cite Share Download PDF Status: Published Journal Publication published 13 Mar, 2026 Read the published version in Earth, Planets and Space → Version 1 posted Editorial decision: Minor Revision 21 Nov, 2025 Reviewers agreed at journal 10 Oct, 2025 Reviewers invited by journal 23 Sep, 2025 Editor assigned by journal 18 Sep, 2025 First submitted to journal 16 Sep, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7635028","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":519389071,"identity":"6c72c93d-cef1-49df-b2af-c1a55a807e1d","order_by":0,"name":"Hiroki Ishimaru","email":"","orcid":"","institution":"Kyoto University: Kyoto Daigaku","correspondingAuthor":false,"prefix":"","firstName":"Hiroki","middleName":"","lastName":"Ishimaru","suffix":""},{"id":519389072,"identity":"b461bcc0-8f94-4fa3-9671-c50030abf711","order_by":1,"name":"Shun Imajo","email":"data:image/png;base64,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","orcid":"https://orcid.org/0000-0002-9862-844X","institution":"Kyoto University: Kyoto Daigaku","correspondingAuthor":true,"prefix":"","firstName":"Shun","middleName":"","lastName":"Imajo","suffix":""},{"id":519389073,"identity":"86b901ea-8c67-4c96-9d63-862b7bb190dc","order_by":2,"name":"Yoshizumi Miyoshi","email":"","orcid":"","institution":"Nagoya University: Nagoya Daigaku","correspondingAuthor":false,"prefix":"","firstName":"Yoshizumi","middleName":"","lastName":"Miyoshi","suffix":""},{"id":519389074,"identity":"a46910f6-06be-42ac-989c-b1315e93e104","order_by":3,"name":"Yoichi Kazama","email":"","orcid":"","institution":"Academia Sinica","correspondingAuthor":false,"prefix":"","firstName":"Yoichi","middleName":"","lastName":"Kazama","suffix":""},{"id":519389075,"identity":"5074a3a5-8c28-4c5f-b87f-dcc2c950eb9a","order_by":4,"name":"Kazushi Asamura","email":"","orcid":"","institution":"Japan Aerospace Exploration Agency - Sagamihara Campus: Uchu Koku Kenkyu Kaihatsu Kiko - Sagamihara Campus","correspondingAuthor":false,"prefix":"","firstName":"Kazushi","middleName":"","lastName":"Asamura","suffix":""},{"id":519389076,"identity":"36b1eb40-eb9f-46b4-a4ba-adf2b3b0e4f9","order_by":5,"name":"Ayako Matsuoka","email":"","orcid":"","institution":"Kyoto University: Kyoto Daigaku","correspondingAuthor":false,"prefix":"","firstName":"Ayako","middleName":"","lastName":"Matsuoka","suffix":""},{"id":519389077,"identity":"ec570ae8-fe30-407a-87f6-fc3df98aea5d","order_by":6,"name":"Yoshiya Kasahara","email":"","orcid":"","institution":"Tohoku University: Tohoku Daigaku","correspondingAuthor":false,"prefix":"","firstName":"Yoshiya","middleName":"","lastName":"Kasahara","suffix":""},{"id":519389078,"identity":"f31c5fb2-8334-4ab0-bbea-4579d6003af6","order_by":7,"name":"Shiang-Yu Wang","email":"","orcid":"","institution":"Academia Sinica","correspondingAuthor":false,"prefix":"","firstName":"Shiang-Yu","middleName":"","lastName":"Wang","suffix":""},{"id":519389079,"identity":"3cc0854c-4e13-4ff6-8e48-5617066313a4","order_by":8,"name":"Sunny W. 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