A statistical study of 90–MeV proton events during the rising phase of solar cycle 23 observed with SOHO/ERNE

A statistical study of 90–MeV proton events during the rising phase of solar cycle 23 observed with SOHO/ERNE | 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 Systematic Review A statistical study of 90–MeV proton events during the rising phase of solar cycle 23 observed with SOHO/ERNE Firas Al-Hamadani, Amjad Al-Sawad This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7840430/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 This study aims to comprehend solar and interplanetary (IP) phenomena generating solar energetic particle (SEP) events with proton energies exceeding 90MeV and identify the locations and commencement times of proton acceleration during such events. Forty energetic proton events, with intensities surpassing 10^−3 cm ^−2 sr^ −1 MeV^ −1 at ∼ 94MeV, were meticulously selected from observations by the Energetic and Relativistic Nuclei and Electrons (ERNE) instrument onboard the Solar and Heliospheric Observatory (SOHO) during solar cycle 23. Using the fixed path length method (1.2AU) and velocity dispersion analysis (VDA), we estimated particle injection times, cross-validating results with the height of radio type II/IV burst emission and comparing them with flare and coronal mass ejection (CME) characteristics. All analyzed proton events were associated with CMEs, 27 with on-the-disk soft X-ray flares, and two void of any flare signatures. Radio type II/IV burst emission association was significant, and for non-associated events, one lacked radio emission while the other exhibited metric continuum and tilted type III burst lane emission. Protons were predominantly injected when CME leading edges were below 5R , reaching peak intensities above 10R preceding the potential passage of IP shocks. In events where the CME front surpassed the estimated type II burst location, we propose a connection between type II bursts, CME interaction processes, and shocks at the CME flanks. Coronal mass ejections. Solar ares. Energetic particles Protons Propagation Radio bursts Meter-wavelengths and longer (m dkm hm km) Type II Full Text Additional Declarations No competing interests reported. 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. 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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-7840430","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Systematic Review","associatedPublications":[],"authors":[{"id":529569068,"identity":"f3e32931-928f-4358-8a2f-99f625ddce8d","order_by":0,"name":"Firas Al-Hamadani","email":"data:image/png;base64,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","orcid":"","institution":"University of Basrah","correspondingAuthor":true,"prefix":"","firstName":"Firas","middleName":"","lastName":"Al-Hamadani","suffix":""},{"id":529569069,"identity":"6014875e-fe14-4a26-a13d-fa9f0724c5de","order_by":1,"name":"Amjad Al-Sawad","email":"","orcid":"","institution":"Ministry of higher education and scientific research","correspondingAuthor":false,"prefix":"","firstName":"Amjad","middleName":"","lastName":"Al-Sawad","suffix":""}],"badges":[],"createdAt":"2025-10-12 11:53:30","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7840430/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7840430/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":93999126,"identity":"f87ce60a-2c88-486f-a2ea-4a4c62fbd616","added_by":"auto","created_at":"2025-10-21 07:42:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1696312,"visible":true,"origin":"","legend":"","description":"","filename":"SEP.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7840430/v1/8c816890afc8012a26f5fcb3.pdf"},{"id":93999125,"identity":"7863105a-ef1f-41ed-b7dc-d58bcce1fc8f","added_by":"auto","created_at":"2025-10-21 07:42:02","extension":"json","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":4145,"visible":true,"origin":"","legend":"","description":"","filename":"bef5721faf73467286c52bf659008d1d.json","url":"https://assets-eu.researchsquare.com/files/rs-7840430/v1/3c1db9c03e1572594a87db67.json"},{"id":93999217,"identity":"e2161340-4f02-4cff-a557-ef0361d11471","added_by":"auto","created_at":"2025-10-21 07:50:03","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":764230,"visible":true,"origin":"","legend":"","description":"","filename":"SEP.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7840430/v1_covered_f8646e26-2965-4be0-97a3-c287da123d03.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A statistical study of 90–MeV proton events during the rising phase of solar cycle 23 observed with SOHO/ERNE","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"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":"Coronal mass ejections. Solar ares. Energetic particles, Protons, Propagation, Radio bursts, Meter-wavelengths and longer (m, dkm, hm, km), Type II","lastPublishedDoi":"10.21203/rs.3.rs-7840430/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7840430/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"This study aims to comprehend solar and interplanetary (IP) phenomena generating solar energetic particle (SEP) events with proton energies exceeding 90MeV and identify the locations and commencement times of proton acceleration during such events. Forty energetic proton events, with intensities surpassing 10^−3 cm ^−2 sr^ −1 MeV^ −1 at ∼ 94MeV, were meticulously selected from observations by the Energetic and Relativistic Nuclei and Electrons (ERNE) instrument onboard the Solar and Heliospheric Observatory (SOHO) during solar cycle 23. Using the fixed path length method (1.2AU) and velocity dispersion analysis (VDA), we estimated particle injection times, cross-validating results with the height of radio type II/IV burst emission and comparing them with flare and coronal mass ejection (CME) characteristics. All analyzed proton events were associated with CMEs, 27 with on-the-disk soft X-ray flares, and two void of any flare signatures. Radio type II/IV burst emission association was significant, and for non-associated events, one lacked radio emission while the other exhibited metric continuum and tilted type III burst lane emission. Protons were predominantly injected when CME leading edges were below 5R , reaching peak intensities above 10R preceding the potential passage of IP shocks. 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