Generating burning plasmas with improved implosions in the Hybrid-E platform

Improving the performance of implosions on NIF by increasing the energy coupled to the capsule has been a strategy pursued in the last several years. The main challenge in improving the energy coupling is in increasing the hohlraum efficiency while maintaining both control over the radiation drive symmetry and key implosion parameters, such as the implosion velocity and coast time. Improved hohlraum efficiency with symmetry control was recently demonstrated in the ‘Hybrid E’ platform[1], which introduces a small amount of wavelength detuning (Dl) to alter the amount of cross-beam energy transfer and increase drive on the hohlraum waist. Recent work has increased the velocity and increased the late-time ablation pressure as the capsule implodes, both of which lead to large increases in stagnation pressure and implosion performance, with the yield tripling from earlier results. These implosions have now entered the burning plasma regime[2-4], with Qa ~ 1.5. A detailed comparison of the increased stagnation pressure with these key design parameters, and expected scaling relations, will be discussed to guide the path forward towards even higher implosion performance.  

 

[1] A.B. Zylstra et al., Phys. Rev. Lett. 126, 025001 (2021) 

[2] A.B. Zylstra, O.A. Hurricane, et al., submitted to Nature (2021) 

[3] J.S. Ross, J.E. Ralph, A.B. Zylstra, et al., submitted to Nature Physics (2021) 

[4] A.L. Kritcher, C.V. Young, H.F. Robey, et al., submitted to Nature Physics (2021)