Dynamics and Power Balance of Near Unity Target Gain Inertial Confinement Fusion Implosions

The change in the power balance, temporal dynamics, emission weighted size, temperature, mass, and areal density of inertially confined fusion plasmas have been quantified for experiments that reach target gains up to 0.72. It is observed that as the target gain rises, increased rates of self-heating initially overcome expansion power losses. This leads to reacting plasmas that reach peak fusion production at later times with increased size, temperature, mass and with lower emission weighted areal densities. Analytic models are consistent with the observations and inferences for how these quantities evolve as the rate of fusion self heating, fusion yield, and target gain increase. At peak fusion production, it is found that as temperatures and target gains rise, the expansion power loss increases to a near constant ratio of the fusion self-heating power. This is consistent with models that indicate that the expansion losses dominate the dynamics in this regime.

Automated summary

The quantification of various parameters in experiments on inertially confined fusion plasmas with target gains up to 0.72 reveals that increased rates of self-heating initially compensate for expansion power losses. As target gain rises, reacting plasmas reach peak fusion production at later times with increased size, temperature, mass, and lower emission weighted areal densities. Analytical models support these observations and provide insights into the evolution of these variables.