High energy gain of ion-driven flux compression in cylindrical target with initial power-law radial density profile

Abstract

The magnetized target fusion (MTF) concept is considered an economic way to harness fusion energy that resides between two ICF and MCF pathways. Here, we have proposed a new DT fuel initial density profile that improves final fusion yield in cylindrical targets in MTF. We have employed the Deira-4 MHD code to investigate the performance of these configurations. The potential advantage of an initial density gradient over a common uniform profile assumption in inertial fusion energy is its higher energy gain at the cost of lower input driver energy. It was shown that its energy gain is higher by a factor of two and reduction in driver input energy by a factor of three for a fixed DT fuel mass regime, m_DT∼2.2 mg. The radial density profile of DT fuel also promises to make larger targets that work at a sub-MJ regime which resolves our concern about the Rayleigh-Taylor instability growth rate during the implosion phase. It has also been shown that the best results with a seed axial magnetic field ∼10 T would be achieved for a power-law density profile, ρ∝rⁿ, with an exponent n=3. Moreover, the optimal target geometry attains for initial aspect ratio of ∼15 and ignition threshold reduced from <ρR>_DT,th=0.56 g/cm² in uniform density of DT fuel to the power law density profile of ρ∝r³ to <ρR>_DT,th =0.21 g/cm².