Use this URL to cite or link to this record in EThOS: | https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.730153 |
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Title: | Temperature and density measurements of plasmas | ||||||
Author: | Kozlowski, Pawel |
ISNI:
0000 0004 6494 7658
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Awarding Body: | University of Oxford | ||||||
Current Institution: | University of Oxford | ||||||
Date of Award: | 2016 | ||||||
Availability of Full Text: |
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Abstract: | |||||||
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). 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 ne ~ 4.3 x 1023 cm-3, temperatures of Te ~ 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 ? ~ 1.33 nm was consistent with the predicted mean free path, and therefore the thickness of the shock. 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 ne ~ 1.0 x 1017 cm-3 , and Te ~ 1.5 eV, consistent with measurements from interferometry and emission spectroscopy.
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Supervisor: | Gregori, Gianluca | Sponsor: | European Research Council ; University of Rochester | ||||
Qualification Name: | Thesis (Ph.D.) | Qualification Level: | Doctoral | ||||
EThOS ID: | uk.bl.ethos.730153 | DOI: | Not available | ||||
Keywords: | plasma physics ; Physics ; Plasma ; Laboratory Astrophysics ; X-ray Thomson Scattering ; Langmuir Probes ; HEDP ; Lab Astro ; High Energy Density Physics ; XRTS ; Astrophysics | ||||||
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