Edge axisymmetric low frequency mode driven by sawtooth-transported energetic particles prior to ITB formation in a Tokamak plasma

Edge axisymmetric low frequency mode driven by sawtooth-transported energetic particles prior to ITB formation in a Tokamak plasma | 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 Article Edge axisymmetric low frequency mode driven by sawtooth-transported energetic particles prior to ITB formation in a Tokamak plasma Liqing Xu, Wei Shen, Zhiyong Qiu, Tianfu Zhou, Yuqi Chu, Chaowei Mai, and 9 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9288752/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Modes with toroidal symmetry (n=0) play a pivotal role in enhancing confinement performance in magnetically confined fusion devices. Here, we report the experimental discovery of a global n=0 mode prior to the formation of an ion internal transport barrier (ITB) in neutral beam-heated plasmas on the EAST tokamak. This mode manifests simultaneously in the ITB region and the plasma edge. We identify that the zonal structure within the ITB region facilitates barrier formation, while the edge-localized, poloidal mode number m=1 dominant structure significantly improves fast ion confinement. Further analysis reveals that this edge n=0 mode is driven by fast ion radial transport induced by core sawtooth crashes, representing a novel non-local excitation mechanism. This mechanism is substantiated by hybrid simulations using the M3D-K code. These findings provide a new perspective on the non-local coupling between core and edge dynamics, offering crucial insights for alpha particle heating and transport in future fusion reactors. Physical sciences/Physics/Plasma physics/Magnetically confined plasmas Physical sciences/Physics/Nuclear physics/Experimental nuclear physics Full Text Additional Declarations There is NO Competing Interest. Cite Share Download PDF Status: Under Review Version 1 posted 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-9288752","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":626351346,"identity":"3544b209-c889-4ea5-9bac-1c1b72a3be16","order_by":0,"name":"Liqing 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