Different effects of a laser prepulse on the proton generation between plastic and metal targets irradiated by an ultraintense laser pulse

Abstract

The effect of a laser prepulse on the generation of proton beams is compared between plastic and metal targets by irradiating a 30fs, 2.4×1018W∕cm2 Ti:sapphire laser pulse. Proton energies generated from both target materials increase as the pulse duration of the laser prepulse decreases. However, it was found that there are distinct differences with respect to target materials. In the case of aluminum targets, as target thickness decreases, proton energy gets higher, which is well described by an isothermal expansion model. However, in the case of Mylar® targets, no such dependence on target thickness could be observed, and the highest maximum proton energies are higher by factors of 1.5 to 3 than those from aluminum targets or those predicted by the isothermal expansion model. Such characteristics of the proton beams from Mylar® targets can be accounted for by a bulk acceleration model, or acceleration by a resistively induced electric field.

Generation of a quasi-monoenergetic high energy proton beam from a vacuum-sandwiched double layer target irradiated by an ultraintense laser pulse

“…For the parameters used in the simulation, the Debye length is estimated to be k De ' 0:25 lm, which is obtained for a laser absorption fraction of 23%. 34,35 Then, the corresponding layer thicknesses are d 1 ¼ 20k De and d 2 ¼ d g ¼ 1:6k De , being similar with the target condition used in the fluid analysis. Layer I is initially positioned at 10 lm away from the left boundary of the simulation box where the laser pulse is launched.…”

Energetic proton beams from plastic targets irradiated by an ultra-intense laser pulse

“…Lee et al 15 also observed how the maximum proton energy varies on the laser pre-pulse for target materials and thickness. As shown in Fig.…”