Enhanced TNSA Ion Acceleration via Optical Confinement and Geometric Plasma Focusing in Annular Sector Targets

Enhanced TNSA Ion Acceleration via Optical Confinement and Geometric Plasma Focusing in Annular Sector Targets | 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 Enhanced TNSA Ion Acceleration via Optical Confinement and Geometric Plasma Focusing in Annular Sector Targets Mohammad Rezaei-Pandari, Mahdi Shayganmanesh, Mohammad Hossein Mahdieh This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8751647/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Enhancing the conversion efficiency and maximum energy of laser-driven ion beams is a critical challenge for applications in hadron therapy and high-energy density physics. In this work, we present a comprehensive two-dimensional Particle-In-Cell (PIC) simulation study comparing Target Normal Sheath Acceleration (TNSA) from standard flat foils and novel annular sector (C-shaped) targets. Under identical ultra-intense laser irradiation (a0=10, t=25 fs, the annular sector geometry demonstrates a substantial enhancement in acceleration performance driven by two synergistic mechanisms: electromagnetic cavity confinement and geometric plasma focusing. Our analysis reveals that the target void acts as an optical trap, sustaining oscillating electromagnetic fields for over 300 fs via multiple internal reflections. This confinement results in a total laser energy absorption of 49(compared to 16% for flat targets), which yields a peak electron temperature of 5.1 MeV—more than double the 2.2 MeV observed in flat targets. Furthermore, phase space diagnostics confirm that ion bunches accelerated from the converging cavity walls superimpose at the geometric center, creating a localized high-density focal spot. Consequently, the annular target increases the proton cut-off energy to 22 MeV (vs. 12 MeV for flat targets) and boosts Carbon ion energies beyond 60 MeV. These findings establish that tailoring target curvature to exploit optical trapping and geometric focusing offers a robust pathway for developing compact, high-efficiency laser-ion sources. High Energy and Particle Physics Optics/Lasers Laser-driven ion acceleration Target Normal Sheath Acceleration (TNSA) Annular sector target Optical confinement Geometric plasma focusing Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted 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-8751647","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":583595783,"identity":"8edb9b01-7faf-4e5d-953d-cee10cc9468d","order_by":0,"name":"Mohammad Rezaei-Pandari","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA00lEQVRIiWNgGAWjYNACAxDBfABISMiQooUtAaSFhxSreMAaCWsxb29/+OFDAUM0g3TP51c3aix4GNgPH92AT4vMmQPJkjMMGHIbZM5us845BnQYT1raDXxaJCQSDkjzgLRI5G4zzmEDapHgMcOvRf5h8+8/YC05z4xz/hGjRYKZTZoBooX5cW4bMVp40tgsewwkcttkjpkx5/ZJ8LAR9Av78cc3fvyxye2Xbn78OedbnRw/++FjeLXAdDKwgREQsBGhHK6L+QPxqkfBKBgFo2AkAQDarz6kzKqL5gAAAABJRU5ErkJggg==","orcid":"","institution":"Department of physics, Iran University of Science and Technology, Narmak, Tehran, Iran","correspondingAuthor":true,"prefix":"","firstName":"Mohammad","middleName":"","lastName":"Rezaei-Pandari","suffix":""},{"id":583595784,"identity":"c0b13402-7f9d-4992-89d0-c133b6fb1d17","order_by":1,"name":"Mahdi Shayganmanesh","email":"","orcid":"","institution":"Department of physics, Iran University of Science and Technology, Narmak, Tehran, Iran","correspondingAuthor":false,"prefix":"","firstName":"Mahdi","middleName":"","lastName":"Shayganmanesh","suffix":""},{"id":583595785,"identity":"25cbf25c-5366-4fcc-b298-cafeceea8dec","order_by":2,"name":"Mohammad Hossein Mahdieh","email":"","orcid":"","institution":"Department of physics, Iran University of Science and Technology, Narmak, Tehran, Iran","correspondingAuthor":false,"prefix":"","firstName":"Mohammad","middleName":"Hossein","lastName":"Mahdieh","suffix":""}],"badges":[],"createdAt":"2026-01-31 17:30:29","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-8751647/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8751647/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":101754252,"identity":"e942ac5d-7b05-463f-9572-baf425a8a606","added_by":"auto","created_at":"2026-02-03 10:42:09","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4338633,"visible":true,"origin":"","legend":"","description":"","filename":"ArxivTNSARezaei.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8751647/v1_covered_c7c0e118-5558-4fb2-a971-4638e086e926.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003eEnhanced TNSA Ion Acceleration via Optical Confinement and Geometric Plasma Focusing in Annular Sector Targets\u003c/p\u003e","fulltext":[],"fulltextSource":"","fullText":"","funders":[{"identity":"c83a5aa1-8e50-471d-8988-f87db5d615ce","identifier":"10.13039/501100003968","name":"Iran National Science Foundation","awardNumber":"4036338","order_by":0}],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Iran University of Science and Technology","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Laser-driven ion acceleration, Target Normal Sheath Acceleration (TNSA), Annular sector target,Optical confinement,Geometric plasma focusing","lastPublishedDoi":"10.21203/rs.3.rs-8751647/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8751647/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eEnhancing the conversion efficiency and maximum energy of laser-driven ion beams is a critical challenge for applications in hadron therapy and high-energy density physics. In this work, we present a comprehensive two-dimensional Particle-In-Cell (PIC) simulation study comparing Target Normal Sheath Acceleration (TNSA) from standard flat foils and novel annular sector (C-shaped) targets. Under identical ultra-intense laser irradiation (a0=10, t=25 fs, the annular sector geometry demonstrates a substantial enhancement in acceleration performance driven by two synergistic mechanisms: electromagnetic cavity confinement and geometric plasma focusing. Our analysis reveals that the target void acts as an optical trap, sustaining oscillating electromagnetic fields for over 300 fs via multiple internal reflections. This confinement results in a total laser energy absorption of 49(compared to 16% for flat targets), which yields a peak electron temperature of 5.1 MeV—more than double the 2.2 \u0026nbsp;MeV observed in flat targets. 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