Collimated proton beams from magnetized near-critical plasmas

Abstract

AbstractGeneration of collimated proton beams by linearly and circularly polarized (CP) lasers from magnetized near-critical plasmas has been investigated with the help of three-dimensional (3D) particle-in-cell (PIC) simulations. Due to cyclotron effects, the transverse proton momentum gets significantly reduced in the presence of an axial magnetic field which leads to an enhancement in collimation. Collimation is observed to be highest in case of a linearly polarized (LP) laser in the presence of magnetic field. However, protons accelerated by a right CP laser in the presence of magnetic field are not only highly collimated but are also more energetic than those accelerated by the LP laser. Although, the presence of an axial magnetic field enhances the collimation by reducing the transverse proton momentum, the maximum proton energy gets reduced since the transverse proton momentum has a significant contribution towards proton energy.