Fusion yield rate recovery by escaping hot-spot fast ions in the neighboring fuel layer

¹ Theoretical Division, Los Alamos National Laboratory - Los Alamos, NM 87545, USA
² Department of Physics, University of Texas - Austin, TX, USA

Received: 7 January 2014
Accepted: 31 January 2014

Abstract

Free-streaming loss by fast ions can deplete the tail population in the hot spot of an inertial confinement fusion (ICF) target. Escaping fast ions in the neighboring fuel layer of a cryogenic target can produce a surplus of fast ions locally. In contrast to the Knudsen layer effect that reduces hot-spot fusion reactivity due to tail ion depletion, the inverse Knudsen layer effect increases fusion reactivity in the neighboring fuel layer. In the case of a burning ICF target in the presence of significant hydrodynamic mix which aggravates the Knudsen layer effect, the yield recovery largely compensates for the yield reduction. For mix-dominated sub-ignition targets, the yield reduction is the dominant process.