Generation of intense proton beams from plastic targets irradiated by an ultraintense laser pulse

Abstract

Proton beams generated from thin aluminum and Mylar foil targets that are irradiated by a 30fs Ti:sapphire laser pulse with an intensity of 2.2x10;{18}Wcm;{2} were investigated. Protons from the Mylar targets were observed to have an energy higher by a factor of 2 and were higher in number by an order of magnitude as compared with those generated from the aluminum targets. The maximum proton energy of 1.3+/-0.12MeV obtained from the Mylar target was found to be similar with previous observations that used laser pulses with different intensities. To address the anomalous behavior of the maximum proton energy for plastic targets, an acceleration model is proposed. In this model, the protons are accelerated by a resistively induced electric field in the front of the target, which can account for the experimental observations.

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

“…First of all, plastic targets generate more protons by orders of magnitude with higher energy by a few factors, which have been already observed in several experiments. [37][38][39] In both materials, the maximum proton energy increases as the duration of the ASE pulse decreases. However, in the case of aluminum targets, the highest maximum energy increases as target thickness decreases, while no such dependence can be found for Mylar ® targets.…”

“…It has been shown that more intense proton beams from the plastic target than those from a metal target can be explained by the ARIE model in the intensity range of 10 17 -10 19 W / cm 2 . 37 In this model, the maximum proton energy is written as the following:…”

“…In the case of metal targets, Fuchs et al 34,35 have shown that in the intensity range of 10 18 -10 20 W / cm 2 , protons accelerated from the rear side of targets are dominant, which is well described by the isothermal plasma expansion model, 36 or target normal sheath acceleration ͑TNSA͒ model. Lee et al 37 have proposed a bulk acceleration model, or acceleration by a resistively induced electric field ͑ARIE͒ to account for more intense proton beams from plastic targets than those from metal targets [37][38][39] with a laser intensity lower than 10 19 W / cm 2 .…”

Ion shock acceleration by large amplitude slow ion acoustic double layers in laser-produced plasmas

“…The interaction of an intense laser beam with an underdense plasma can lead to rapid heating of the electrons and acceleration of ions [8,9]. In target normal sheath acceleration (TNSA) [10][11][12][13][14][15][16][17][18][19], a minority species of light ions (typically protons) is accelerated by the hot sheath of laser-heated electrons normal to a solid target. The TNSA scheme has successfully been used to accelerate protons to several tens of MeV, usually with a wide spectrum of energies [18].…”

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

“…The target normal sheath acceleration (TNSA) model 4 or the isothermal expansion model 5 is known to effectively describe the proton beam from metal foils. 7 Acceleration by a resistively induced electric field (ARIE) 8,9 has been proposed to account for the phenomena occurring in plastic foils.…”