Magnetic field generation in a cylindrical plasma using the density gradient

In this research, we use the fluid theory in an efficient way to perform a theoretical study on a divergent flux of fast electrons produced during interaction of a high-power laser beam with a cylindrical over-dense target. Cylindrical targets consisting of a low-density core with high-density cladding structures are irradiated by an ultra-intense annular laser beam. The analytical model exhibits such structures with a density gradient generating a strong spontaneous interface magnetic field that can collimate the fast electron beam and prevent electrons from escaping. The magnetic field generated by such a cylindrical target is compared with that of planar targets. The results show that cylindrical structures have a more effective potential for producing spontaneous interface magnetic fields and reducing the transverse angular distribution of the fast electron beam. Thus, they will be adequate to increase the possibility of energy transmission to the main target for a more promising fast ignition scheme in inertial confinement fusion.