Editing Inertial confinement fusion (section)

=== Polymer fuel capsule fabrication ===
For fuel capsules constructed using glow-discharge polymer (GDP) via [[plasma polymerization]], outer diameters can range from 900&nbsp;μm (typical for the OMEGA laser system at the [[Laboratory for Laser Energetics]]) to 2mm (typical for the [[National Ignition Facility|NIF]] laser at the [[Lawrence Livermore National Laboratory]].
The process for producing GDP capsules begins with a bubble of poly([[α-methylstyrene]]) (PAMS) that serves as a decomposable mandrel. Next, the bubble is coated with GDP to the desired thickness. Finally, the coated bubble is heated in an inert atmosphere. Upon reaching 300&nbsp;°C, the PAMS bubble decomposes into its monomers and diffuses out of the coating, leaving only a hollow sphere of the GDP coating.<ref>K. R. Schultz, J. L. Kaae, W. J. Miller, D. A. Steinman, and R. B. Stephens, "Status of inertial fusion target fabrication in the USA," Fusion Engineering and Design, vol. 44, no. 1, pp. 441–448, 1999, doi: https://doi.org/10.1016/S0920-3796(98)00356-1.</ref>

GDP lends itself to inertial fusion capsules—especially those used in direct-drive configurations—due to its ability to create low-defect, uniform thin films that are permeable to deuterium and tritium fuel. Permeating the fuel into the capsule precludes the need for drilling into the capsule to facilitate fuel injection, reducing the overall fusion target complexity and asymmetry. The rigorous uniformity and sphericity requirements of direct drive fusion experiments result in GDP being favored over other capsule materials. Additionally, the GDP layers can be doped with different elements to provide diagnostic signals or prevent preheating of the fuel.<ref>"2 Technical Background." National Research Council. 2013. Assessment of Inertial Confinement Fusion Targets. Washington, DC: The National Academies Press. doi: 10.17226/18288. National Academies of Sciences, Engineering, and Medicine. 2013. Assessment of Inertial Confinement Fusion Targets. Washington, DC: The National Academies Press. https://doi.org/10.17226/18288.</ref>