{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/85170"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/85170","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Empirical Constraints on O(5+) Outflows and Velocity Distributions in a Solar-Minimum Coronal Streamer","abstract":"As part of an effort to understand how the solar wind is energized, the so-determined electron density is used to interpret O VI lambda1032, 1037 A spectra taken with UVCS. The spectra are interpreted in terms of empirical constraints on the O5+ ion velocity distributions and outflow speeds. Four conclusions result from this work: (1) our analysis shows O5+ velocity distribution anisotropy in the streamer legs and stalk and also shows that the microscopic velocity distribution (which excludes wave motions that equally affect all charged particles) is anisotropic, where the most probable speed perpendicular to the magnetic field direction exceeds that in the parallel direction; (2) there is preferential heating of the O5+ ions over the protons in the streamer stalk and legs; (3) there is no evidence for preferential O5+ heating in the core; (4) the outflow velocity of the O5+ ions is determined at heights above 4.6 R⊙ . All results have a confidence level of at least 70%.","abstract_html":"As part of an effort to understand how the solar wind is energized, the so-determined electron density is used to interpret O VI lambda1032, 1037 A spectra taken with UVCS. The spectra are interpreted in terms of empirical constraints on the O5+ ion velocity distributions and outflow speeds. Four conclusions result from this work: (1) our analysis shows O5+ velocity distribution anisotropy in the streamer legs and stalk and also shows that the microscopic velocity distribution (which excludes wave motions that equally affect all charged particles) is anisotropic, where the most probable speed perpendicular to the magnetic field direction exceeds that in the parallel direction; (2) there is preferential heating of the O5+ ions over the protons in the streamer stalk and legs; (3) there is no evidence for preferential O5+ heating in the core; (4) the outflow velocity of the O5+ ions is determined at heights above 4.6 R⊙ . All results have a confidence level of at least 70%.","abstract_has_math":false,"creators":["Frazin, Richard Alan"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Astronomy","degree_department":null,"school":null,"contributors":["Mihalas, Dimitri"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-25T22:35:35Z","date_published":"2015-09-25T22:35:35Z","updated_at":"2026-07-22T22:26:24Z","subjects":["Physics, Astronomy and Astrophysics"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI3044089"],"render_values":[{"text":"(MiAaPQ)AAI3044089","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/85170","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Mihalas, Dimitri"]},{"key":"dc:creator","label":"Author","values":["Frazin, Richard Alan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-25T22:35:35Z","10000-01-01","2002"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Astronomy"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Physics, Astronomy and Astrophysics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/85170","(MiAaPQ)AAI3044089"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["As part of an effort to understand how the solar wind is energized, the so-determined electron density is used to interpret O VI lambda1032, 1037 A spectra taken with UVCS. The spectra are interpreted in terms of empirical constraints on the O5+ ion velocity distributions and outflow speeds. Four conclusions result from this work: (1) our analysis shows O5+ velocity distribution anisotropy in the streamer legs and stalk and also shows that the microscopic velocity distribution (which excludes wave motions that equally affect all charged particles) is anisotropic, where the most probable speed perpendicular to the magnetic field direction exceeds that in the parallel direction; (2) there is preferential heating of the O5+ ions over the protons in the streamer stalk and legs; (3) there is no evidence for preferential O5+ heating in the core; (4) the outflow velocity of the O5+ ions is determined at heights above 4.6 R⊙ . All results have a confidence level of at least 70%.","Made available in DSpace on 2015-09-25T22:35:35Z (GMT). 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The spectra are interpreted in terms of empirical constraints on the O5+ ion velocity distributions and outflow speeds. Four conclusions result from this work: (1) our analysis shows O5+ velocity distribution anisotropy in the streamer legs and stalk and also shows that the microscopic velocity distribution (which excludes wave motions that equally affect all charged particles) is anisotropic, where the most probable speed perpendicular to the magnetic field direction exceeds that in the parallel direction; (2) there is preferential heating of the O5+ ions over the protons in the streamer stalk and legs; (3) there is no evidence for preferential O5+ heating in the core; (4) the outflow velocity of the O5+ ions is determined at heights above 4.6 R⊙ . All results have a confidence level of at least 70%.","Made available in DSpace on 2015-09-25T22:35:35Z (GMT). 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