Fast Ignition Laser Fusion Using In-Situ Ion Acceleration With Pulsed CO2 Lasers

Fast ignition is an alternative concept of laser fusion in which the task of compressing the fusion pellet to supersolid densities is accomplished by the conventional high energy nanosecond glass lasers and the task of igniting the compressed pellet is given to a high intensity, moderate energy pico second source which can set the pellet ablaze (with DT fusion reactions) by creating an adequate size hot spot in it. In this letter, we present a conceptual method by which energy from carbon dioxide ($ CO_2 $) laser could be coupled to heat up ions produced in situ in the plasma, which in turn produces the required hot spot. An efficient conversion of $ CO_2 $ energy into ion beam energy can thus give us the required source of energy for the fast ignition laser fusion. We demonstrate by using PIC (Particle - In - Cell) simulations that the use of several Kilo Tesla of an external magnetic field in the transverse direction in an inhomogeneous plasma where a cutoff is followed by a resonance can lead to coupling of laser energy to a lower hybrid ion plasma resonance. Then ions are accelerated efficiently ($\sim 1 MeV$) by the breaking of lower hybrid waves and thereby enabling the possibility of fast ignition by ions in a convenient fashion.