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Effect of Target Material on Fast Electron Transport
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| 자료유형 | 학위논문 |
|---|---|
| 서명/저자사항 | Effect of Target Material on Fast Electron Transport. |
| 개인저자 | Chawla, Sugreev. |
| 단체저자명 | University of California, San Diego. Mechanical and Aerospace Engineering. |
| 발행사항 | [S.l.]: University of California, San Diego., 2019. |
| 발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
| 형태사항 | 140 p. |
| 기본자료 저록 | Dissertations Abstracts International 81-02B. Dissertation Abstract International |
| ISBN | 9781085569439 |
| 학위논문주기 | Thesis (Ph.D.)--University of California, San Diego, 2019. |
| 일반주기 |
Source: Dissertations Abstracts International, Volume: 81-02, Section: B.
Advisor: Beg, Farhat. |
| 이용제한사항 | This item must not be sold to any third party vendors. |
| 요약 | In cone-guided fast ignition (FI) inertial confinement fusion, successful ignition relies on the efficient transport of a relativistic electron beam (REB) through a solid density cone tip to a high-density fuel core. A variety of physics mechanisms affect the quality of beam transport, and these effects vary with tip material. This thesis presents a systematic study of the effect of tip material on REB transport.An experiment was performed using the Titan laser (150 J, 0.7 ps pulse duration, 1 關m wavelength) at LLNL on multilayered targets with varying transport layers. A more collimated electron beam was consistently observed using high- or mid-Z transport layers as compared to low Z layers, without a significant loss in forward-going electron energy flux. PIC simulations agreed well with experiments, showing the formation of strong resistive magnetic channels (~80 MG ) enveloped by a global B-field that collimate initially divergent fast electrons (in high-Z targets). These results illustrated the dynamic competition between stopping and collimation that is essential to understand in order to optimize electron flux levels.Hybrid-PIC simulations further investigated transport in various materials at Titan laser conditions. REB energy loss from stopping was similar in low- and mid-Z materials (21-27%), and much higher in Au (54%), dominated by ohmic stopping. Resistive magnetic field growth was shown to depend on the dynamic competition between the resistivity and resistivity gradient source terms in Faraday's Law. Resistivity evolution, in addition, was shown to depend on the Spitzer-like competition between the ionization state and temperature growth rates. Results suggest that, at Titan conditions, mid-atomic number materials like Cu and Ag are optimal for collimation.This work has significant implications for fast ignition. At FI conditions, more energy will be injected into the cone tip very quickly, leading to faster ionization and heating rates. Higher atomic number materials may be favorable at these conditions as ionization can continue for a longer period during a ~20 ps FI pulse. These results motivate further computational and experimental work to investigate how multilayer targets can be exploited to maximize fast electron beam collimation whilst minimizing deposition rates. |
| 일반주제명 | Plasma physics. |
| 언어 | 영어 |
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: 이 자료의 원문은 한국교육학술정보원에서 제공합니다. |
