{"id":"https://openalex.org/W2897017316","doi":"https://doi.org/10.3390/e20100799","title":"Long-Term Independence of Solar Wind Polytropic Index on Plasma Flow Speed","display_name":"Long-Term Independence of Solar Wind Polytropic Index on Plasma Flow Speed","publication_year":2018,"publication_date":"2018-10-17","ids":{"openalex":"https://openalex.org/W2897017316","doi":"https://doi.org/10.3390/e20100799","mag":"2897017316","pmid":"https://pubmed.ncbi.nlm.nih.gov/33265886"},"language":"en","primary_location":{"id":"doi:10.3390/e20100799","is_oa":true,"landing_page_url":"https://doi.org/10.3390/e20100799","pdf_url":"https://www.mdpi.com/1099-4300/20/10/799/pdf?version=1539776284","source":{"id":"https://openalex.org/S195231649","display_name":"Entropy","issn_l":"1099-4300","issn":["1099-4300"],"is_oa":true,"is_in_doaj":true,"is_core":true,"host_organization":"https://openalex.org/P4310310987","host_organization_name":"Multidisciplinary Digital Publishing Institute","host_organization_lineage":["https://openalex.org/P4310310987"],"host_organization_lineage_names":["Multidisciplinary Digital Publishing Institute"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Entropy","raw_type":"journal-article"},"type":"article","indexed_in":["crossref","doaj","pubmed"],"open_access":{"is_oa":true,"oa_status":"gold","oa_url":"https://www.mdpi.com/1099-4300/20/10/799/pdf?version=1539776284","any_repository_has_fulltext":true},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5080379161","display_name":"G. Livadiotis","orcid":"https://orcid.org/0000-0002-7655-6019"},"institutions":[{"id":"https://openalex.org/I1290463931","display_name":"Southwest Research Institute","ror":"https://ror.org/03tghng59","country_code":"US","type":"nonprofit","lineage":["https://openalex.org/I1290463931"]}],"countries":["US"],"is_corresponding":true,"raw_author_name":"George Livadiotis","raw_affiliation_strings":["Division of Space Science and Engineering, Southwest Research Institute, San Antonio, TX 78238, USA"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Division of Space Science and Engineering, Southwest Research Institute, San Antonio, TX 78238, USA","institution_ids":["https://openalex.org/I1290463931"]}]}],"institutions":[],"countries_distinct_count":1,"institutions_distinct_count":1,"corresponding_author_ids":["https://openalex.org/A5080379161"],"corresponding_institution_ids":["https://openalex.org/I1290463931"],"apc_list":{"value":2600,"currency":"CHF","value_usd":3137},"apc_paid":{"value":2600,"currency":"CHF","value_usd":3137},"fwci":3.1351,"has_fulltext":true,"cited_by_count":50,"citation_normalized_percentile":{"value":0.91643942,"is_in_top_1_percent":false,"is_in_top_10_percent":true},"cited_by_percentile_year":{"min":89,"max":99},"biblio":{"volume":"20","issue":"10","first_page":"799","last_page":"799"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T10251","display_name":"Solar and Space Plasma Dynamics","score":0.9998999834060669,"subfield":{"id":"https://openalex.org/subfields/3103","display_name":"Astronomy and Astrophysics"},"field":{"id":"https://openalex.org/fields/31","display_name":"Physics and Astronomy"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},"topics":[{"id":"https://openalex.org/T10251","display_name":"Solar and Space Plasma Dynamics","score":0.9998999834060669,"subfield":{"id":"https://openalex.org/subfields/3103","display_name":"Astronomy and Astrophysics"},"field":{"id":"https://openalex.org/fields/31","display_name":"Physics and Astronomy"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T10159","display_name":"Ionosphere and magnetosphere dynamics","score":0.9979000091552734,"subfield":{"id":"https://openalex.org/subfields/3103","display_name":"Astronomy and Astrophysics"},"field":{"id":"https://openalex.org/fields/31","display_name":"Physics and Astronomy"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T11405","display_name":"Geophysics and Gravity Measurements","score":0.9966999888420105,"subfield":{"id":"https://openalex.org/subfields/1910","display_name":"Oceanography"},"field":{"id":"https://openalex.org/fields/19","display_name":"Earth and Planetary Sciences"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}}],"keywords":[{"id":"https://openalex.org/keywords/polytropic-process","display_name":"Polytropic process","score":0.9825221300125122},{"id":"https://openalex.org/keywords/solar-wind","display_name":"Solar wind","score":0.7593374848365784},{"id":"https://openalex.org/keywords/physics","display_name":"Physics","score":0.6782659888267517},{"id":"https://openalex.org/keywords/plasma","display_name":"Plasma","score":0.4569580554962158},{"id":"https://openalex.org/keywords/mechanics","display_name":"Mechanics","score":0.42986056208610535},{"id":"https://openalex.org/keywords/computational-physics","display_name":"Computational physics","score":0.35659894347190857},{"id":"https://openalex.org/keywords/meteorology","display_name":"Meteorology","score":0.3418620228767395},{"id":"https://openalex.org/keywords/nuclear-physics","display_name":"Nuclear physics","score":0.07554417848587036}],"concepts":[{"id":"https://openalex.org/C142475440","wikidata":"https://www.wikidata.org/wiki/Q831024","display_name":"Polytropic process","level":2,"score":0.9825221300125122},{"id":"https://openalex.org/C108411613","wikidata":"https://www.wikidata.org/wiki/Q79833","display_name":"Solar wind","level":3,"score":0.7593374848365784},{"id":"https://openalex.org/C121332964","wikidata":"https://www.wikidata.org/wiki/Q413","display_name":"Physics","level":0,"score":0.6782659888267517},{"id":"https://openalex.org/C82706917","wikidata":"https://www.wikidata.org/wiki/Q10251","display_name":"Plasma","level":2,"score":0.4569580554962158},{"id":"https://openalex.org/C57879066","wikidata":"https://www.wikidata.org/wiki/Q41217","display_name":"Mechanics","level":1,"score":0.42986056208610535},{"id":"https://openalex.org/C30475298","wikidata":"https://www.wikidata.org/wiki/Q909554","display_name":"Computational physics","level":1,"score":0.35659894347190857},{"id":"https://openalex.org/C153294291","wikidata":"https://www.wikidata.org/wiki/Q25261","display_name":"Meteorology","level":1,"score":0.3418620228767395},{"id":"https://openalex.org/C185544564","wikidata":"https://www.wikidata.org/wiki/Q81197","display_name":"Nuclear physics","level":1,"score":0.07554417848587036}],"mesh":[],"locations_count":4,"locations":[{"id":"doi:10.3390/e20100799","is_oa":true,"landing_page_url":"https://doi.org/10.3390/e20100799","pdf_url":"https://www.mdpi.com/1099-4300/20/10/799/pdf?version=1539776284","source":{"id":"https://openalex.org/S195231649","display_name":"Entropy","issn_l":"1099-4300","issn":["1099-4300"],"is_oa":true,"is_in_doaj":true,"is_core":true,"host_organization":"https://openalex.org/P4310310987","host_organization_name":"Multidisciplinary Digital Publishing Institute","host_organization_lineage":["https://openalex.org/P4310310987"],"host_organization_lineage_names":["Multidisciplinary Digital Publishing Institute"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Entropy","raw_type":"journal-article"},{"id":"pmid:33265886","is_oa":false,"landing_page_url":"https://pubmed.ncbi.nlm.nih.gov/33265886","pdf_url":null,"source":{"id":"https://openalex.org/S4306525036","display_name":"PubMed","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I1299303238","host_organization_name":"National Institutes of Health","host_organization_lineage":["https://openalex.org/I1299303238"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Entropy (Basel, Switzerland)","raw_type":"Journal Article"},{"id":"pmh:oai:pubmedcentral.nih.gov:7512360","is_oa":true,"landing_page_url":"https://www.ncbi.nlm.nih.gov/pmc/articles/7512360","pdf_url":null,"source":{"id":"https://openalex.org/S2764455111","display_name":"PubMed Central","issn_l":null,"issn":null,"is_oa":true,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I1299303238","host_organization_name":"National Institutes of Health","host_organization_lineage":["https://openalex.org/I1299303238"],"host_organization_lineage_names":[],"type":"repository"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"Entropy (Basel)","raw_type":"Text"},{"id":"pmh:oai:doaj.org/article:27432029a57a4a629a005a9278f1ed6f","is_oa":true,"landing_page_url":"https://doaj.org/article/27432029a57a4a629a005a9278f1ed6f","pdf_url":null,"source":{"id":"https://openalex.org/S4306401280","display_name":"DOAJ (DOAJ: Directory of Open Access Journals)","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":null,"host_organization_name":null,"host_organization_lineage":[],"host_organization_lineage_names":[],"type":"repository"},"license":"cc-by-sa","license_id":"https://openalex.org/licenses/cc-by-sa","version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"Entropy, Vol 20, Iss 10, p 799 (2018)","raw_type":"article"}],"best_oa_location":{"id":"doi:10.3390/e20100799","is_oa":true,"landing_page_url":"https://doi.org/10.3390/e20100799","pdf_url":"https://www.mdpi.com/1099-4300/20/10/799/pdf?version=1539776284","source":{"id":"https://openalex.org/S195231649","display_name":"Entropy","issn_l":"1099-4300","issn":["1099-4300"],"is_oa":true,"is_in_doaj":true,"is_core":true,"host_organization":"https://openalex.org/P4310310987","host_organization_name":"Multidisciplinary Digital Publishing Institute","host_organization_lineage":["https://openalex.org/P4310310987"],"host_organization_lineage_names":["Multidisciplinary Digital Publishing Institute"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Entropy","raw_type":"journal-article"},"sustainable_development_goals":[{"id":"https://metadata.un.org/sdg/7","score":0.8999999761581421,"display_name":"Affordable and clean energy"}],"awards":[{"id":"https://openalex.org/G253484353","display_name":"1. MOTIVATION, SCIENCE GOAL&OBJECTIVES  IN COLLISIONLESS PLASMAS SUCH AS THE SOLAR WIND, THE COUPLING BETWEEN PLASMA CONSTITUENTS AND THE EMBEDDED M","funder_award_id":"NNX17AB74G","funder_id":"https://openalex.org/F4320306101","funder_display_name":"National Aeronautics and Space Administration"}],"funders":[{"id":"https://openalex.org/F4320306101","display_name":"National Aeronautics and Space Administration","ror":"https://ror.org/027ka1x80"}],"has_content":{"grobid_xml":true,"pdf":true},"content_urls":{"pdf":"https://content.openalex.org/works/W2897017316.pdf","grobid_xml":"https://content.openalex.org/works/W2897017316.grobid-xml"},"referenced_works_count":47,"referenced_works":["https://openalex.org/W826830734","https://openalex.org/W1553495501","https://openalex.org/W1746269545","https://openalex.org/W1977721011","https://openalex.org/W1981533735","https://openalex.org/W2000594240","https://openalex.org/W2005260522","https://openalex.org/W2009049561","https://openalex.org/W2009586635","https://openalex.org/W2031021978","https://openalex.org/W2033751654","https://openalex.org/W2034179117","https://openalex.org/W2039102180","https://openalex.org/W2043784086","https://openalex.org/W2050941779","https://openalex.org/W2051201249","https://openalex.org/W2058348810","https://openalex.org/W2080414626","https://openalex.org/W2097208940","https://openalex.org/W2106628253","https://openalex.org/W2148041461","https://openalex.org/W2155179652","https://openalex.org/W2165864744","https://openalex.org/W2170733202","https://openalex.org/W2193573619","https://openalex.org/W2324443365","https://openalex.org/W2483389846","https://openalex.org/W2510907192","https://openalex.org/W2524498983","https://openalex.org/W2535607760","https://openalex.org/W2563203903","https://openalex.org/W2595204592","https://openalex.org/W2625882416","https://openalex.org/W2748487762","https://openalex.org/W2759633664","https://openalex.org/W2768596536","https://openalex.org/W2777488007","https://openalex.org/W2785731430","https://openalex.org/W2786065877","https://openalex.org/W2790395485","https://openalex.org/W2884571279","https://openalex.org/W2891790758","https://openalex.org/W3099887482","https://openalex.org/W3104685435","https://openalex.org/W3176606732","https://openalex.org/W6644602617","https://openalex.org/W6685171329"],"related_works":["https://openalex.org/W2748952813","https://openalex.org/W2064462859","https://openalex.org/W3126201635","https://openalex.org/W4285227925","https://openalex.org/W2947852619","https://openalex.org/W1943883417","https://openalex.org/W2261950160","https://openalex.org/W4311452595","https://openalex.org/W2170733202","https://openalex.org/W2019276593"],"abstract_inverted_index":{"The":[0,77,137,173],"paper":[1],"derives":[2],"the":[3,7,15,38,48,52,68,73,82,87,98,106,125,128,133,143,152,156,169],"polytropic":[4,53,83,99,129,138,153],"indices":[5],"over":[6],"last":[8],"two":[9],"solar":[10,16,69,116,135,157],"cycles":[11],"(years":[12],"1995\u20132017)":[13],"for":[14],"wind":[17,70,117,158],"proton":[18,29,159],"plasma":[19,30,107,160,170],"near":[20,161],"Earth":[21],"(~1":[22],"AU).":[23],"We":[24],"use":[25],"~92-s":[26],"datasets":[27],"of":[28,51,67,75,81,89,115,124,127,155,168],"moments":[31],"(speed,":[32],"density,":[33],"and":[34,61,72,178],"temperature),":[35],"measured":[36],"from":[37],"Solar":[39],"Wind":[40,44],"Experiment":[41],"instrument":[42],"onboard":[43],"spacecraft,":[45],"to":[46,105],"estimate":[47],"moving":[49],"averages":[50],"index,":[54],"as":[55,57,64],"well":[56],"their":[58],"weighted":[59,176],"means":[60],"standard":[62,180],"errors":[63],"a":[65],"function":[66],"speed":[71],"year":[74],"measurements.":[76],"derived":[78],"long-term":[79],"behavior":[80],"index":[84,100,130,139,154],"agrees":[85],"with":[86,103,112],"results":[88],"other":[90],"previous":[91],"methods.":[92],"In":[93],"particular,":[94],"we":[95],"find":[96],"that":[97,122],"remains":[101,140],"quasi-constant":[102],"respect":[104],"flow":[108,171],"speed,":[109],"in":[110,132],"agreement":[111],"earlier":[113],"analyses":[114],"plasma.":[118],"It":[119],"is":[120,182],"shown":[121],"most":[123],"fluctuations":[126],"appear":[131],"fast":[134],"wind.":[136],"quasi-constant,":[141],"despite":[142],"frequent":[144],"entropic":[145],"variations.":[146],"Therefore,":[147],"on":[148],"an":[149],"annual":[150],"basis,":[151],"~1":[162],"AU":[163],"can":[164],"be":[165],"considered":[166],"independent":[167],"speed.":[172],"estimated":[174],"all-year":[175],"mean":[177],"its":[179],"error":[181],"\u03b3":[183],"=":[184],"1.86":[185],"\u00b1":[186],"0.09.":[187]},"counts_by_year":[{"year":2026,"cited_by_count":2},{"year":2025,"cited_by_count":8},{"year":2024,"cited_by_count":8},{"year":2023,"cited_by_count":4},{"year":2022,"cited_by_count":5},{"year":2021,"cited_by_count":7},{"year":2020,"cited_by_count":6},{"year":2019,"cited_by_count":9},{"year":2018,"cited_by_count":1}],"updated_date":"2026-08-27T14:10:00.468798","created_date":"2025-10-10T00:00:00"}
