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Surface-Morphology Effect on Physical Sputtering of Plasma-Facing Materials
Surface-Morphology Effect on Physical Sputtering of Plasma-Facing Materials
상세정보
- 자료유형
- 학위논문 서양
- 최종처리일시
- 20250211153029
- ISBN
- 9798346867319
- DDC
- 530
- 저자명
- Chang, Feng-Jen.
- 서명/저자
- Surface-Morphology Effect on Physical Sputtering of Plasma-Facing Materials
- 발행사항
- [Sl] : University of California, San Diego, 2024
- 발행사항
- Ann Arbor : ProQuest Dissertations & Theses, 2024
- 형태사항
- 145 p
- 주기사항
- Source: Dissertations Abstracts International, Volume: 86-06, Section: B.
- 주기사항
- Advisor: Tynan, George R.
- 학위논문주기
- Thesis (Ph.D.)--University of California, San Diego, 2024.
- 초록/해제
- 요약For magnetic confinement fusion reactors, physical sputtering of the plasma-facing materials (PFMs) can influence the lifetime of PFMs and the migration of impurities. During plasma exposure, the surface morphology of a PFM can be modified, resulting in the formation of complex submicron-scale structures. This dissertation demonstrates how such modifications can influence physical sputtering of PFM, the subsequent transport and migration of the physically sputtered impurities. In Chapter 3, the microscopic cone structures that can spontaneously form on a Cr surface physically sputtered by He plasma are studied in the PISCES-A linear plasma device with hyperspectral imaging measurements and in simulations that couple SDTrimSP and GITR codes. Due to line-of-sight redeposition of sputtered Cr atoms onto cone structures, the effective sputtering yield is reduced, and the angular distributions at smaller angles with respect to the macroscopic surface normal is enhanced. In Chapter 4, the influence of fuzz structures on physical sputtering of Mo by He plasma is studied using the similar methods. While sputtering yield reduction due to the line-of-sight redeposition in the fuzz layer is confirmed, fuzz structures do not influence the angular distributions of sputtered Mo significantly. According to the depth profile of the differential sputtering yield from the simulations, a simple analytical model that characterizes the fuzz layer by a single collision mean free path is proposed, which successfully explains the effect of fuzz on physical sputtering. In Chapter 5, how angular distributions of physically sputtered W influence migration of W in the ITER divertor region is conceptually studied using ERO 2.0 simulations. When using simple idealized unidirectional distributions, the line-of-sight redeposition locations of W atoms clearly vary with the direction of the initial velocity. However, despite the differences between the angular distributions of W sputtered on a flat surface and on a fuzzy surface, the corresponding W deposition profiles look similar, since the suppression of neutral W atom population by ionization dominates the profiles, enhancing atomic deposition at locations closer to the strike points. From the results of this dissertation, the influence of surface morphology should be considered when studying physically sputtered impurities.
- 일반주제명
- Plasma physics
- 일반주제명
- Nuclear physics
- 일반주제명
- Nuclear engineering
- 키워드
- Nuclear fusion
- 기타저자
- University of California, San Diego Mechanical and Aerospace Engineering
- 기본자료저록
- Dissertations Abstracts International. 86-06B.
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
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■00520250211153029
■006m o d
■007cr#unu||||||||
■020 ▼a9798346867319
■035 ▼a(MiAaPQ)AAI31634696
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a530
■1001 ▼aChang, Feng-Jen.
■24510▼aSurface-Morphology Effect on Physical Sputtering of Plasma-Facing Materials
■260 ▼a[Sl]▼bUniversity of California, San Diego▼c2024
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2024
■300 ▼a145 p
■500 ▼aSource: Dissertations Abstracts International, Volume: 86-06, Section: B.
■500 ▼aAdvisor: Tynan, George R.
■5021 ▼aThesis (Ph.D.)--University of California, San Diego, 2024.
■520 ▼aFor magnetic confinement fusion reactors, physical sputtering of the plasma-facing materials (PFMs) can influence the lifetime of PFMs and the migration of impurities. During plasma exposure, the surface morphology of a PFM can be modified, resulting in the formation of complex submicron-scale structures. This dissertation demonstrates how such modifications can influence physical sputtering of PFM, the subsequent transport and migration of the physically sputtered impurities. In Chapter 3, the microscopic cone structures that can spontaneously form on a Cr surface physically sputtered by He plasma are studied in the PISCES-A linear plasma device with hyperspectral imaging measurements and in simulations that couple SDTrimSP and GITR codes. Due to line-of-sight redeposition of sputtered Cr atoms onto cone structures, the effective sputtering yield is reduced, and the angular distributions at smaller angles with respect to the macroscopic surface normal is enhanced. In Chapter 4, the influence of fuzz structures on physical sputtering of Mo by He plasma is studied using the similar methods. While sputtering yield reduction due to the line-of-sight redeposition in the fuzz layer is confirmed, fuzz structures do not influence the angular distributions of sputtered Mo significantly. According to the depth profile of the differential sputtering yield from the simulations, a simple analytical model that characterizes the fuzz layer by a single collision mean free path is proposed, which successfully explains the effect of fuzz on physical sputtering. In Chapter 5, how angular distributions of physically sputtered W influence migration of W in the ITER divertor region is conceptually studied using ERO 2.0 simulations. When using simple idealized unidirectional distributions, the line-of-sight redeposition locations of W atoms clearly vary with the direction of the initial velocity. However, despite the differences between the angular distributions of W sputtered on a flat surface and on a fuzzy surface, the corresponding W deposition profiles look similar, since the suppression of neutral W atom population by ionization dominates the profiles, enhancing atomic deposition at locations closer to the strike points. From the results of this dissertation, the influence of surface morphology should be considered when studying physically sputtered impurities.
■590 ▼aSchool code: 0033.
■650 4▼aPlasma physics
■650 4▼aNuclear physics
■650 4▼aNuclear engineering
■653 ▼aImpurity transport
■653 ▼aLinear plasma device
■653 ▼aNuclear fusion
■653 ▼aPhysical sputtering
■653 ▼aPlasma-material interaction
■653 ▼aSurface morphology
■690 ▼a0759
■690 ▼a0552
■690 ▼a0756
■71020▼aUniversity of California, San Diego▼bMechanical and Aerospace Engineering.
■7730 ▼tDissertations Abstracts International▼g86-06B.
■790 ▼a0033
■791 ▼aPh.D.
■792 ▼a2024
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17164664▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
