High Performance Glow Discharge Polymer (GDP) Based Ablators

Fusion ignition in a controlled laboratory environment was achieved for the first time on December 4th, 2022, unlocking the promise of unlimited energy supply. This fusion process utilizes a hollow spherical ablator capsule, potentially made of HDC (a form of nanocrystalline diamond), GDP, or beryllium. HDC is currently the material of choice in these experiments, but GDP offers some advantages that make it an attractive alternative.

GDP is a relatively mature ablator material to the ICF community, with benefits in high ablation efficiency, low adiabat potential, amorphous (therefore no inhomogeneity that arise from the grain structure), and easy to dope (for preheat control). However, it suffers drawbacks in two distinctive areas: (1) Tiny debris on the mandrel substrate or from the coating process can cause undesirable dome growth that can seed hydrodynamic instabilities during the shot (2) Dangling bonds within the ablator material can interact with oxygen and moisture to cause gradual and potentially nonuniform variations in properties (e.g. composition, density, etc). In this work, we will explore new methods to better control these two aspects of the GDP properties. Parametric studies of GDP fabrication and properties in relation to dome growth and oxygen uptake will also be presented.