Research Of Enhanced Target Normal Sheath Acceleration Based On Interaction Between Laser And Plasma Waveguide Target

The interaction of the laser pulse with the relativistic intensity with the plasma can generate an accelerating electric field that is more than three orders of magnitude higher than that of the conventional accelerator,so that the particles can be accelerated more efficiently,and the energy of the particles can be raised to the required level in the desktop scale.Based on the previous work,this paper conducts theoretical analysis and numerical simulation on an enhanced target normal sheath acceleration(TNSA)scheme.Our main conclusions are as follows:First,the plasma waveguide can be used as an optical converter to modulate a super-high-Gaussian laser to produce a unique high-order-mode laser.Due to the difference in the velocity of these higher-order modes,the order increases gradually from the wavefront to the tail.In the high-order mode amplification region,the intensity of the longitudinal electric field is increased by at least an order of magnitude from its initial value.We also establish a simple theoretical model for predicting the distribution and intensity of the longitudinal electric field.Although the model is not completely relativistic,the consis-tency of the theoretical results with the simulation results proves that the linear eigen-mode structure is robust,and this model is also applicable to high-intensity laser pulses.A discussion of the relevant parameters indicates that the optical mode transitions in the plasmonic waveguide are suitable for different laser intensities,polarization states,and angles of incidence.Second,the energy conversion efficiency of relativistic ultrashort laser pulses to ions can be greatly improved by an enhanced TNSA scheme using a plasma waveguide target(PWT).The laser pulse with an intensity of 4.3×10²⁰W/cm²,pulse duration of 26.7fs and an energy of 1.53 J,the maximum energy of protons and carbon ions obtained by interaction with the PWT target can reach 46 Me V and 150 Me V,respectively.The corresponding laser pulse to ion energy conversion efficiency can be as high as 15%.We also proposed a theoretical model of full 3D dynamics analysis.The results of theoretical model predictions of ion energy dependence on laser and PWT parameters are in good agreement with numerical simulation results.The effectively improved energy conversion efficiency and robustness to various parameters indicate that the scheme should be suitable for applications in inertial confinement fusion(ICF),laser accelerators,compact neutron sources,and medical treatment.Third,we studied a relative long(hundreds of fs)TNSA scheme for the interaction of laser pulses with a silk target(WT).Compared to the classical flat target(PT)scheme,the use of a silk target(WT)can effectively increase the max energy?_maxand energy conversi efficiency?of protron and Carbon ions,which is about 3 times that of the classic PT.The energy conversion efficiency of laser to ions can even reach 40%.The nature of the protons and ions obtained by the acceleration can also be adjusted by controlling the laser and line array parameters.Therefore,the TNSA program should be applicable to tumor treatment,rapid ignition and other applications in inertial confinement fusion.