{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/85942"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/85942","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Beam-Ion Transport in Tokamaks: Thermalization in Large Orbit-Width Regime","abstract":"\"Comparison with the present results shows that the small orbit-width approximation introduces $\\ge$5% errors in the density, parallel momentum, and energy moments when $\\rho\\sb{\\theta}/L = 0.86$ in low-$Z\\sb{\\rm eff}$ plasmas. These results are observed for all source pitch-angles studied except the deeply passing sources, which are in good agreement ($\\le$5%) with the small orbit-width model. A non-zero current, due to the large orbit-width of the trapped fast ions, is identified and related to, the superthermal alpha particle bootstrap \"\"seed\"\" current. In low-$Z\\sb{\\rm eff}$ plasmas, pitch-angle scattering is only important for marginally passing ion sources. Scattering into the trapping region causes substantial inward-directed transport that is not predicted in the convective model. Parallel momentum is reduced by $\\sim$70%. For cases with marginally passing sources in higher $Z\\sb{\\rm eff}$ plasmas, transport into the trapping region scales linearly with scattering frequency $\\nu\\sb{\\perp}.$ The results are sensitive to source localization in a layer at the trapping/passing boundary. Significant broadening of profiles is observed for cases with deeply trapped sources in higher $Z\\sb{\\rm eff}$ plasmas.\"","abstract_html":"&quot;Comparison with the present results shows that the small orbit-width approximation introduces $\\ge$5% errors in the density, parallel momentum, and energy moments when <span class=\"etd-inline-math\">\\rho\\sb{&theta;}/L = 0.86</span> in low-$Z\\sb{\\rm eff}$ plasmas. These results are observed for all source pitch-angles studied except the deeply passing sources, which are in good agreement ($\\le$5%) with the small orbit-width model. A non-zero current, due to the large orbit-width of the trapped fast ions, is identified and related to, the superthermal alpha particle bootstrap &quot;&quot;seed&quot;&quot; current. In low-$Z\\sb{\\rm eff}$ plasmas, pitch-angle scattering is only important for marginally passing ion sources. Scattering into the trapping region causes substantial inward-directed transport that is not predicted in the convective model. Parallel momentum is reduced by $\\sim$70%. For cases with marginally passing sources in higher $Z\\sb{\\rm eff}$ plasmas, transport into the trapping region scales linearly with scattering frequency $\\nu\\sb{\\perp}.$ The results are sensitive to source localization in a layer at the trapping/passing boundary. Significant broadening of profiles is observed for cases with deeply trapped sources in higher $Z\\sb{\\rm eff}$ plasmas.&quot;","abstract_has_math":true,"creators":["Sager, Glenn Terry"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Nuclear Engineering","degree_department":null,"school":null,"contributors":["George Hunter Miley"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-28T14:51:22Z","date_published":"2015-09-28T14:51:22Z","updated_at":"2026-07-22T22:26:26Z","subjects":["Engineering, Nuclear"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI9904576"],"render_values":[{"text":"(MiAaPQ)AAI9904576","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/85942","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["George Hunter Miley"]},{"key":"dc:creator","label":"Author","values":["Sager, Glenn Terry"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-28T14:51:22Z","10000-01-01","1998"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Nuclear Engineering"]},{"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":["Engineering, Nuclear"]}]},{"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/2142/85942","(MiAaPQ)AAI9904576"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["\"Comparison with the present results shows that the small orbit-width approximation introduces $\\ge$5% errors in the density, parallel momentum, and energy moments when $\\rho\\sb{\\theta}/L = 0.86$ in low-$Z\\sb{\\rm eff}$ plasmas. These results are observed for all source pitch-angles studied except the deeply passing sources, which are in good agreement ($\\le$5%) with the small orbit-width model. A non-zero current, due to the large orbit-width of the trapped fast ions, is identified and related to, the superthermal alpha particle bootstrap \"\"seed\"\" current. In low-$Z\\sb{\\rm eff}$ plasmas, pitch-angle scattering is only important for marginally passing ion sources. Scattering into the trapping region causes substantial inward-directed transport that is not predicted in the convective model. Parallel momentum is reduced by $\\sim$70%. For cases with marginally passing sources in higher $Z\\sb{\\rm eff}$ plasmas, transport into the trapping region scales linearly with scattering frequency $\\nu\\sb{\\perp}.$ The results are sensitive to source localization in a layer at the trapping/passing boundary. Significant broadening of profiles is observed for cases with deeply trapped sources in higher $Z\\sb{\\rm eff}$ plasmas.\"","Made available in DSpace on 2015-09-28T14:51:22Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 9904576.pdf: 3873068 bytes, checksum: ecbaa39b81da7af88cdea7ad0757d982 (MD5) Previous issue date: 1998","Embargo set by: Seth Robbins for item 87223 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","159 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1998."]},{"key":"dc:title","label":"Title","values":["Beam-Ion Transport in Tokamaks: Thermalization in Large Orbit-Width Regime"]}]}],"canonical_facts":{"dc:contributor":["George Hunter Miley"],"dc:creator":["Sager, Glenn Terry"],"dc:date":["2015-09-28T14:51:22Z","10000-01-01","1998"],"dc:description":["\"Comparison with the present results shows that the small orbit-width approximation introduces $\\ge$5% errors in the density, parallel momentum, and energy moments when $\\rho\\sb{\\theta}/L = 0.86$ in low-$Z\\sb{\\rm eff}$ plasmas. These results are observed for all source pitch-angles studied except the deeply passing sources, which are in good agreement ($\\le$5%) with the small orbit-width model. A non-zero current, due to the large orbit-width of the trapped fast ions, is identified and related to, the superthermal alpha particle bootstrap \"\"seed\"\" current. In low-$Z\\sb{\\rm eff}$ plasmas, pitch-angle scattering is only important for marginally passing ion sources. Scattering into the trapping region causes substantial inward-directed transport that is not predicted in the convective model. Parallel momentum is reduced by $\\sim$70%. For cases with marginally passing sources in higher $Z\\sb{\\rm eff}$ plasmas, transport into the trapping region scales linearly with scattering frequency $\\nu\\sb{\\perp}.$ The results are sensitive to source localization in a layer at the trapping/passing boundary. Significant broadening of profiles is observed for cases with deeply trapped sources in higher $Z\\sb{\\rm eff}$ plasmas.\"","Made available in DSpace on 2015-09-28T14:51:22Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 9904576.pdf: 3873068 bytes, checksum: ecbaa39b81da7af88cdea7ad0757d982 (MD5) Previous issue date: 1998","Embargo set by: Seth Robbins for item 87223 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","159 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1998."],"dc:identifier":["http://hdl.handle.net/2142/85942","(MiAaPQ)AAI9904576"],"dc:language":["eng"],"dc:subject":["Engineering, Nuclear"],"dc:title":["Beam-Ion Transport in Tokamaks: Thermalization in Large Orbit-Width Regime"],"dc:type":["text"],"thesis:degree_discipline":["Nuclear Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:26Z"}