Energy deposition of MeV electrons in compressed targets of fast-ignition inertial confinement fusion

Abstract

Energy deposition of MeV electrons in dense plasmas, important for fast ignition in inertial confinement fusion, is modeled analytically. It is shown that classical stopping and scattering dominate electron transport and energy deposition when the electrons reach the dense plasmas in the cores of compressed targets, while “anomalous” stopping associated with self-generated fields and micro-instabilities (suggested by previous simulations) might initially play an important role in the lower-density plasmas outside the dense core. For MeV electrons in precompressed deuterium-tritium fast-ignition targets, the initial penetration results in approximately uniform energy deposition but the latter stages of penetration involve mutual couplings of energy loss, straggling, and blooming that lead to enhanced, nonuniform energy deposition. This model can be used for quantitatively assessing ignition requirements for fast ignition.