Two-dimensional magnetohydrodynamic modeling of cylindrical plasma jets confined magneto-inertial fusion targets
Date of Award
Doctor of Philosophy (PhD)
Mechanical and Aerospace Engineering
Inertial confinement fusion., Plasma jets.
A set of 2D time-dependent simulations of an imploding cylindrical target and liner are presented. The 2D model developed for this dissertation was used to evaluate these assumptions and explore the ignition space for PJMIF in cylindrical geometries. The 2D magnetohydrodynamic (MHD) model was discretized using smoothed particle hydrodynamics (SPH). The energy term within the equations was augmented with three volumetric power models, including the fusion power produced by alpha particle heating, Bremsstrahlung radiation, and thermal conduction. The original power balance models guided the choice of a reference case for the new 2D MHD simulation. This baseline case consisted of a cylindrical target and liner with a hot inner target at a temperature of 5 keV compressed by a cold multilayer liner at 2.5 eV. The multilayer liner consisted of an inner layer of deuterium and tritium (DT) and an outer thicker layer of Argon to act as a confinement device. The initial density and radius of the target were 5.5 kg/m3 and 30 cm giving a ρR= 0.165 g/cm2. The reference case produced a gain of three. A parametric analysis was then conducted, varying the target: density, temperature, radius, and liner inner/outer thickness ratio to understand scaling of gain sensitivity while assessing the assumptions of simpler models that have established the original motivations and theoretical underpinnings of PJMIF and more generally MIF. This work did not find a region in which compression by a plasma liner was capable of bringing a target to ignition conditions. However, it was determined that a multilayer plasma liner was able to contain a thermally conditioned target and allow it to achieve fusion ignition and positive gain. Numerical analysis indicated that energy conducted from the target to the inner liner was able to ignite the inner liner DT. Liner ignition enabled the overall fusion gain to increase and shows that secondary burn of a surrounding cold fuel layer is possible. It was found that thermal conduction from the hotspot to the cold fuel layer was important for this secondary burn. Additionally, a comparison of these results to previous analysis showed agreement between the regions of positive heating.
Thompson, Seth, "Two-dimensional magnetohydrodynamic modeling of cylindrical plasma jets confined magneto-inertial fusion targets" (2019). Dissertations. 193.