Theoretical and Experimental Contributions of MIT to the Fusion Science Center, and Findings of the Electron Transport Task Force

Energy deposition of MeV electrons in dense plasmas, critical for fast ignition in inertial confinement fusion (ICF), 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 pre-compressed deuterium-tritium (DT) fast-ignition targets, while the initial penetration results in approximately uniform energy deposition, the latter stages involve mutual couplings of energy loss, straggling, and blooming that lead to enhanced, non-uniform energy deposition. This model can be used for quantitatively assessing ignition requirements for fast ignition.