Proposed Diagnostic for Measuring Implosion Symmetry and Core Conditions on the National Ignition Facility

Tertiary protons with birth energies from 27 to 30.8MeV result from the implosion of ignition-scale inertial confinement fusion targets, such as those planned for the National Ignition Facility. Measurement of the tertiaries close-quote slowing can provide a determination of the imploded areal density of the fuel capsule, as well as information about implosion asymmetry that results from anisotropy of the areal density and plasma temperature. To determine the utility of tertiaries for all phases of ignition experiments, we analyze three representative cases: a gas capsule (0.7kJ yield), a cryogenic fuel capsule that fails to ignite (15kJ), and a cryogenic fuel capsule that ignites and burns (13000kJ). In each case, tertiaries escape from the capsule and convey critical information about implosion dynamics. copyright 1996 The American Physical Society