Attosecond electron bunch generation by an intense laser propagation in a conical channel with a curved wall

By using two-dimensional particle-in-cell simulations, attosecond electron bunches with high density, high energy, and small divergence angle can be obtained by p-polarized laser irradiation in a conical channel with a curved wall. We find that some electrons in the wall are pulled into the channel by the transverse electric field and are directly accelerated. Meanwhile, they move steadily along the conical wall via laser ponderomotive force. The results show that the focusing effect of the curved wall conical channel is stronger than that of the traditional flat wall conical channel, and the density of the attosecond electron bunches is increased by nearly 175% as well as the maximum energy is increased by 36%. We also find that the quality of the electron bunches is affected by the geometry of the conical channel wall. Interestingly, it is found that the attosecond electron bunches obtained from the specific conical channel with the hyperbolic geometry of the curved wall can keep stable around the maximum electron energy within 10T0 even if they have left the channel.