Turbulent dynamo in the terrestrial magnetosheath

Turbulent dynamo in the terrestrial magnetosheath | 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 Physical Sciences - Article Turbulent dynamo in the terrestrial magnetosheath Zoltan Voros, Roberts Owen, Yasuhito Narita, Emiliya Yordanova, and 9 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6454585/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 18 Feb, 2026 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Abstract Dynamo action refers to energy exchange processes through which magnetic fields are generated or/and amplified at the expense of kinetic energy of the plasma flows in various laboratory, space and astrophysical environments. The generation of the magnetic fields can take place over multiple spatial scales simultaneously. Flows associ- ated with dynamos can generate magnetic fields on scales larger or smaller than the flows themselves. Multi-scale dynamo processes are fundamental for explaining magnetic fields on various scales, from planetary (e.g. geodynamo) to solar/stellar and (extra-)galactic scales. They are also vital for understanding the generation and amplification of magnetic fields by turbulent flows at smaller scales. Although our understanding of dynamos largely stems from theory and simulations, experimental validation of dynamo action remains confined to labora- tory settings. Here we address the question of experimentally verifying the existence of the turbulent dynamo in the Earth’s magnetosheath, a collisionless, high plasma beta environment. The predictions of dynamo theory and simulations, specifically, the expected spatial topology of stretched and folded magnetic fields, the effect of compres- sions, and the occurrence of pressure anisotropy instabilities necessary for the amplification of magnetic fields, are tested. The observations show that the magnetosheath data clearly exhibit the predicted tur- bulent dynamo signatures. Our findings indicate that the terrestrial magnetosheath, with the available high-resolution, multi-point plasma and field measurements, could become the first space-based testbed for validating turbulent dynamo theories and simulations. We expect that direct and more comprehensive statistical observations of the dynamo in the magnetosheath would markedly broaden the scope of both lab- oratory experiments and numerical simulations encompassing spatial scales pertinent to space and astrophysical environment. Physical sciences/Physics Physical sciences/Physics/Space physics Dynamo turbulence magnetosheath Full Text Additional Declarations There is NO Competing Interest. Cite Share Download PDF Status: Published Journal Publication published 18 Feb, 2026 Read the published version in Nature Communications → 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-6454585","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Physical Sciences - Article","associatedPublications":[],"authors":[{"id":446188691,"identity":"484705f1-df0a-4cba-aa9c-e31280929b86","order_by":0,"name":"Zoltan 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magnetosheath","lastPublishedDoi":"10.21203/rs.3.rs-6454585/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6454585/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Dynamo action refers to energy exchange processes through which\r\nmagnetic fields are generated or/and amplified at the expense of\r\nkinetic energy of the plasma flows in various laboratory, space and\r\nastrophysical environments. The generation of the magnetic fields can\r\ntake place over multiple spatial scales simultaneously. Flows associ-\r\nated with dynamos can generate magnetic fields on scales larger or\r\nsmaller than the flows themselves. Multi-scale dynamo processes are\r\nfundamental for explaining magnetic fields on various scales, from\r\nplanetary (e.g. geodynamo) to solar/stellar and (extra-)galactic scales.\r\nThey are also vital for understanding the generation and amplification\r\nof magnetic fields by turbulent flows at smaller scales. Although our\r\nunderstanding of dynamos largely stems from theory and simulations,\r\nexperimental validation of dynamo action remains confined to labora-\r\ntory settings. Here we address the question of experimentally verifying\r\nthe existence of the turbulent dynamo in the Earth’s magnetosheath,\r\na collisionless, high plasma beta environment. The predictions of\r\ndynamo theory and simulations, specifically, the expected spatial\r\ntopology of stretched and folded magnetic fields, the effect of compres-\r\nsions, and the occurrence of pressure anisotropy instabilities necessary\r\nfor the amplification of magnetic fields, are tested. The observations\r\nshow that the magnetosheath data clearly exhibit the predicted tur-\r\nbulent dynamo signatures. Our findings indicate that the terrestrial\r\nmagnetosheath, with the available high-resolution, multi-point plasma\r\nand field measurements, could become the first space-based testbed for\r\nvalidating turbulent dynamo theories and simulations. We expect that\r\ndirect and more comprehensive statistical observations of the dynamo\r\nin the magnetosheath would markedly broaden the scope of both lab-\r\noratory experiments and numerical simulations encompassing spatial\r\nscales pertinent to space and astrophysical environment.","manuscriptTitle":"Turbulent dynamo in the terrestrial magnetosheath","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-25 01:58:29","doi":"10.21203/rs.3.rs-6454585/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-communications","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"NCOMMS","sideBox":"Learn more about [Nature Communications](http://www.nature.com/ncomms/)","snPcode":"","submissionUrl":"https://mts-ncomms.nature.com/","title":"Nature Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Communications","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"a9434111-331b-4f07-af44-2da0b97362db","owner":[],"postedDate":"April 25th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":47491400,"name":"Physical sciences/Physics"},{"id":47491401,"name":"Physical sciences/Physics/Space physics"}],"tags":[],"updatedAt":"2026-03-28T07:10:38+00:00","versionOfRecord":{"articleIdentity":"rs-6454585","link":"https://doi.org/10.1038/s41467-026-69469-y","journal":{"identity":"nature-communications","isVorOnly":false,"title":"Nature Communications"},"publishedOn":"2026-02-18 05:00:00","publishedOnDateReadable":"February 18th, 2026"},"versionCreatedAt":"2025-04-25 01:58:29","video":"","vorDoi":"10.1038/s41467-026-69469-y","vorDoiUrl":"https://doi.org/10.1038/s41467-026-69469-y","workflowStages":[]},"version":"v1","identity":"rs-6454585","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6454585","identity":"rs-6454585","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}