Experimental measurements of yield amplification in burning and near-ignited plasmas

Previous design changes of inertial confinement fusion implosions have led to MJ-range production of fusion yield on the National Ignition Facility. These fusion plasmas have significant self-heating due to alpha-particle energy deposition, and exhibit non-trivial burn propagation into the dense DT-ice fuel layer. This self-heating drives additional yield production, termed "yield amplification", and ultimately leads to a runaway phenomenon. This process has been observed in several recent HYBRID-E target designs, notably the shot N210808 and its precursor N210307. In order to quantify the performance gain due to this yield amplification, we conducted a pair of experiments replicating those two burning-plasma shots but using a fuel layer dudded with hydrogen which effectively "turns off" the yield amplification. Results from this set of burn-on and burn-off implosions will be presented and discussed, and briefly compared with post-shot simulations and modeling. Values for the yield amplification of N210808 and N210307 will be presented, and we'll discuss trends in the no-alpha DSR with yield-amplification.