Investigations of the Impacts of Multi-ion and Kinetic effects in High-Z doped Inertial Confinement Fusion (ICF) implosions at OMEGA
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vargas-joev-sm-nse-2026-thesis.pdf
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Author(s)
Vargas, Joseph
Advisor(s)
Frenje, Johan A.
Date Issued
February 2026
Publisher
Massachusetts Institute of Technology
Abstract
Using a wealth of data acquired throughout various experimental campaigns executed from 2006 to 2008, the effect of multi-ion and kinetic physics during kinetic phases of inertial confinement fusion (ICF) implosions are quantified. Implosions were performed at the OMEGA laser system, and utilized SiO₂-hoppe-glass targets, filled with varying amounts of D³He and high-Z dopant gases. All 60 beams were pointed to the target chamber center (TCC) and delivered maximum power in either a 1.0 or 0.6 nano-second laser pulse, applying the maximum energy per beam. Using the combined data recorded with the Particle-temporal-diagnostic (PTD), Neutron-temporal diagnostic (NTD) and various time integrated proton spectrometers, spatially-averaged and reaction-weighted DD and D3He ion temperatures and densities were inferred using a dynamic 1D implosion model based on parabolic density and temperature functions. This modelling approach includes underlying physical constraints such as mass conservation, however, neglects multi-ion and kinetic mechanisms, specifically, ion-species separation and thermal decoupling, which occur the during the shock-burn phase of an implosion and affect the temporal evolution of ion density and temperature. In this thesis work, the reaction-weighted, spatially-averaged ion temperatures and densities are inferred using a coupled implosion model, where deuterium and helium-3 temperatures and densities are assumed to evolve together, and a decoupled model where the deuterium and helium-3 densities evolve independently. The results from both models are compared to the time-resolved temperature and density profiles computed using the ion-Fokker-Planck (iFP) code, which applies a kinetic treatment to ion evolution to quantify the level of species separation and thermal decoupling present in these implosions. For comparison, hydrodynamic simulations with the HYADES code are also conducted. The coupled model reproduces the qualitative temperature evolution predicted by iFP, whereas HYADES predicts overly large, short-lived reaction-weighted temperatures. The principal discrepancy appears in the density evolution, where iFP predicts temporal and spatial d/³He separation that cannot be represented by the coupled model. Allowing independent density evolution enables the decoupled framework to recover separation trends consistent with iFP, indicating that multi-ion physics plays a measurable role in these implosions.
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
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