{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/46666"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/46666","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Analysis of energy balance in a helicon coupled to an inertial electrostatic confinement device","abstract":"The characteristics of the helicon plasma injection into the IEC were explored. The first such analysis was a COMSOL simulation to determine the voltage as a function of position in the helicon dielectric tube when the IEC cathode is biased to several kilovolts. This COMSOL simulation contained no plasma and a ~20 V drop in the helicon dielectric tube was determined. To build upon this COMSOL model which contained no plasma, calculations of the theoretical ion flow rates were performed. These calculations used the measured ion current to determine the ionization fraction. Using the ionization fraction as an input into the zero dimensional model an electron temperature was obtained. With the electron temperature, collision and sheath/presheath properties can be determined. Finally entering the collision and presheath/sheath properties into a diffusion equation yields an ion flow rate that was on the same order of magnitude as the measured ion flow rate (~1016 s-1). The similarity between the theoretical calculations with the measured values verified some of the assumptions made in the theoretical calculations. Such assumptions include approximating the voltage drop in the presheath, which includes the length of the helicon dielectric tube, as on the order of the electron temperature ~2.85 eV. This assumption was based on the literature and showed that effects such as Debye shielding play a large role in screening out large cathode biases. So increasing the cathode grid bias does not necessary increase the ion flow rate significantly.","abstract_html":"The characteristics of the helicon plasma injection into the IEC were explored. The first such analysis was a COMSOL simulation to determine the voltage as a function of position in the helicon dielectric tube when the IEC cathode is biased to several kilovolts. This COMSOL simulation contained no plasma and a ~20 V drop in the helicon dielectric tube was determined. To build upon this COMSOL model which contained no plasma, calculations of the theoretical ion flow rates were performed. These calculations used the measured ion current to determine the ionization fraction. Using the ionization fraction as an input into the zero dimensional model an electron temperature was obtained. With the electron temperature, collision and sheath/presheath properties can be determined. Finally entering the collision and presheath/sheath properties into a diffusion equation yields an ion flow rate that was on the same order of magnitude as the measured ion flow rate (~1016 s-1). The similarity between the theoretical calculations with the measured values verified some of the assumptions made in the theoretical calculations. Such assumptions include approximating the voltage drop in the presheath, which includes the length of the helicon dielectric tube, as on the order of the electron temperature ~2.85 eV. This assumption was based on the literature and showed that effects such as Debye shielding play a large role in screening out large cathode biases. So increasing the cathode grid bias does not necessary increase the ion flow rate significantly.","abstract_has_math":false,"creators":["Chen, George"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Nuclear, Plasma, Radiolgc Engr","degree_department":null,"school":null,"contributors":["Miley, George H."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-01-16T17:58:16Z","date_published":"2014-01-16T17:58:16Z","updated_at":"2026-07-22T22:25:36Z","subjects":["Inertial Electrostatic Confinement (IEC)","Helicon","External ion injection","External ion transfer","Helicon ion source","IEC/Helicon coupling"],"languages":["en"],"rights":["Copyright 2013 George Chen. Figures taken from external sources (e.g. publications, books, etc.) belong to their respective owners."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/46666","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Miley, George H."]},{"key":"dc:creator","label":"Author","values":["Chen, George"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-01-16T17:58:16Z","2013-12"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Nuclear, Plasma, Radiolgc Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"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":["Inertial Electrostatic Confinement (IEC)","Helicon","External ion injection","External ion transfer","Helicon ion source","IEC/Helicon coupling"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2013 George Chen. 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Using the ionization fraction as an input into the zero dimensional model an electron temperature was obtained. With the electron temperature, collision and sheath/presheath properties can be determined. Finally entering the collision and presheath/sheath properties into a diffusion equation yields an ion flow rate that was on the same order of magnitude as the measured ion flow rate (~1016 s-1). The similarity between the theoretical calculations with the measured values verified some of the assumptions made in the theoretical calculations. Such assumptions include approximating the voltage drop in the presheath, which includes the length of the helicon dielectric tube, as on the order of the electron temperature ~2.85 eV. This assumption was based on the literature and showed that effects such as Debye shielding play a large role in screening out large cathode biases. So increasing the cathode grid bias does not necessary increase the ion flow rate significantly.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2013-12-09T22:53:57Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 4 Chen_George.pdf: 2270477 bytes, checksum: d99cb7d7c3fb7e5bed9c1bb9afe1b474 (MD5) Chen_George.pdf: 2270477 bytes, checksum: d99cb7d7c3fb7e5bed9c1bb9afe1b474 (MD5) George Chen - MS Thesis ver7.docx: 5175433 bytes, checksum: e6de969da1ca1f99641f2a0036111d28 (MD5) Chen_George.pdf: 2270259 bytes, checksum: 9b7838a06a9019c698c6ffff252fc7a4 (MD5)","Made available in DSpace on 2014-01-16T17:58:16Z (GMT). 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To build upon this COMSOL model which contained no plasma, calculations of the theoretical ion flow rates were performed. These calculations used the measured ion current to determine the ionization fraction. Using the ionization fraction as an input into the zero dimensional model an electron temperature was obtained. With the electron temperature, collision and sheath/presheath properties can be determined. Finally entering the collision and presheath/sheath properties into a diffusion equation yields an ion flow rate that was on the same order of magnitude as the measured ion flow rate (~1016 s-1). The similarity between the theoretical calculations with the measured values verified some of the assumptions made in the theoretical calculations. Such assumptions include approximating the voltage drop in the presheath, which includes the length of the helicon dielectric tube, as on the order of the electron temperature ~2.85 eV. 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Figures taken from external sources (e.g. publications, books, etc.) belong to their respective owners."],"dc:subject":["Inertial Electrostatic Confinement (IEC)","Helicon","External ion injection","External ion transfer","Helicon ion source","IEC/Helicon coupling"],"dc:title":["Analysis of energy balance in a helicon coupled to an inertial electrostatic confinement device"],"dc:type":["text"],"thesis:degree_discipline":["Nuclear, Plasma, Radiolgc Engr"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:36Z"}