Temperature and density measurements of plasmas
<p>Diagnosing the temperatures and densities of plasmas is critical to the understanding of a wide variety of phenomena. Everything from equations of state for warm dense matter (WDM) found in Jovian planets and inertial confinement fusion (ICF) to turbulent and dissipative processes in laser-...
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| Format: | Thesis |
| Language: | English |
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2016
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| _version_ | 1797086425244499968 |
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| author | Kozlowski, P |
| author2 | Gregori, G |
| author_facet | Gregori, G Kozlowski, P |
| author_sort | Kozlowski, P |
| collection | OXFORD |
| description | <p>Diagnosing the temperatures and densities of plasmas is critical to the understanding of a wide variety of phenomena. Everything from equations of state for warm dense matter (WDM) found in Jovian planets and inertial confinement fusion (ICF) to turbulent and dissipative processes in laser-produced plasmas, rely on accurate and precise measurements of temperature and density. This work presents improvements on two distinct techniques for measuring temperatures and densities in plasmas: x-ray Thomson scattering (XRTS), and Langmuir probes (LPs).</p> <p>At the OMEGA laser facility, experiments on warm dense matter were performed by firing lasers at an ablator foil and driving a planar shock into cryogenically cooled liquid deuterium. XRTS in the collective scattering regime was implemented to probe the matter, measuring densities of n<sub>e</sub> ~ 4.3 × 10<sup>23</sup> cm<sup>−3</sup>, temperatures of T<sub>e</sub> ~ 12 eV and ionizations of Z ~ 1.0. Through an extension to XRTS theory for inhomogeneous systems, it was possible to extract an additional parameter, the length scale of the shock, whose value of Λ ~ 1.33 nm was consistent with the predicted mean free path, and therefore the thickness of the shock.</p> <p>A unique triple Langmuir probe prototype was designed and tested at the Gregori group’s lab at the University of Oxford. This probe was designed for a high temporal resolution of ~ 200 MHz for probing laser-produced shocks. The probes were used to measure the shock formed from ablating carbon rods in an argon gas fill. The probe yielded plasma parameters of n<sub>e</sub> ~ 1.0 × 10<sup>17</sup> cm<sup>−3</sup> , and T<sup>e</sup> ~ 1.5 eV, consistent with measurements from interferometry and emission spectroscopy.</p> |
| first_indexed | 2024-03-07T02:21:53Z |
| format | Thesis |
| id | oxford-uuid:a436a632-d5aa-4e1a-8711-3814d059053c |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T02:21:53Z |
| publishDate | 2016 |
| record_format | dspace |
| spelling | oxford-uuid:a436a632-d5aa-4e1a-8711-3814d059053c2022-03-27T02:32:18ZTemperature and density measurements of plasmasThesishttp://purl.org/coar/resource_type/c_db06uuid:a436a632-d5aa-4e1a-8711-3814d059053cPhysicsplasma physicsEnglishORA Deposit2016Kozlowski, PGregori, G<p>Diagnosing the temperatures and densities of plasmas is critical to the understanding of a wide variety of phenomena. Everything from equations of state for warm dense matter (WDM) found in Jovian planets and inertial confinement fusion (ICF) to turbulent and dissipative processes in laser-produced plasmas, rely on accurate and precise measurements of temperature and density. This work presents improvements on two distinct techniques for measuring temperatures and densities in plasmas: x-ray Thomson scattering (XRTS), and Langmuir probes (LPs).</p> <p>At the OMEGA laser facility, experiments on warm dense matter were performed by firing lasers at an ablator foil and driving a planar shock into cryogenically cooled liquid deuterium. XRTS in the collective scattering regime was implemented to probe the matter, measuring densities of n<sub>e</sub> ~ 4.3 × 10<sup>23</sup> cm<sup>−3</sup>, temperatures of T<sub>e</sub> ~ 12 eV and ionizations of Z ~ 1.0. Through an extension to XRTS theory for inhomogeneous systems, it was possible to extract an additional parameter, the length scale of the shock, whose value of Λ ~ 1.33 nm was consistent with the predicted mean free path, and therefore the thickness of the shock.</p> <p>A unique triple Langmuir probe prototype was designed and tested at the Gregori group’s lab at the University of Oxford. This probe was designed for a high temporal resolution of ~ 200 MHz for probing laser-produced shocks. The probes were used to measure the shock formed from ablating carbon rods in an argon gas fill. The probe yielded plasma parameters of n<sub>e</sub> ~ 1.0 × 10<sup>17</sup> cm<sup>−3</sup> , and T<sup>e</sup> ~ 1.5 eV, consistent with measurements from interferometry and emission spectroscopy.</p> |
| spellingShingle | Physics plasma physics Kozlowski, P Temperature and density measurements of plasmas |
| title | Temperature and density measurements of plasmas |
| title_full | Temperature and density measurements of plasmas |
| title_fullStr | Temperature and density measurements of plasmas |
| title_full_unstemmed | Temperature and density measurements of plasmas |
| title_short | Temperature and density measurements of plasmas |
| title_sort | temperature and density measurements of plasmas |
| topic | Physics plasma physics |
| work_keys_str_mv | AT kozlowskip temperatureanddensitymeasurementsofplasmas |