| Generating high energy proton beams with energies up to several MeV via the interaction between super dense and short laser pules and plasma is one of the most interesting physical problems for researchers. The interaction between super dense and short laser pules and plasma would produce high energy electrons with the speed close to the speed of light. These relativistic electrons with super hot temperature interacts with the positively charged protons which are at the surface of the target material after the electrons pass through the target material and produce acceleration electric field up-to 1012 V/m and the protons would acquire energies up-to several tens of MeV after they have been accelerated by the acceleration electric field. Producing high energy protons via the interaction between super dense and short laser pulse and plasma has many creative potential applications in scientific technological areas like new proton accelerators, nuclear fusion generated by proton beams, medical diagnosis and medical treatments.In chapter 1, we briefly introduce super dense and short laser pulse, plasma and present the development and advancements in proton accelerators and inertia constrained nuclear fusion. We also present the methods we use to study the interaction between super dense and short laser pulse and plasma targets.In chapter 2, the principles of generating super hot electrons or high energy proton beams via super dense and short laser pluses is shown, including the parameters that describe the super dense and short laser pulse and plasma, the features of laser propagating in plasma and the TNSA acceleration mechanism in the interaction between super hot electrons and positively charged high energy proton beams.The simulation methods for the interaction between laser and plasma is discussed in chapter 3. We present solving Maxwell’s equation using PIC method, solving the equation for relativistic particles, electric current density and handling initial conditions and boundary conditions.In chapter 4, with the choice of different plasma target materials and using PIC simulation method we study the production of self generated magnetic field and proton acceleration during the interaction between super dense laser pulse and plasma targets. Our result shows that, when the super dense laser with power density of 2201cmW0 interacts with plasma targets, the produced self magnetic fields at the surface of the plasma material causes the space oriented emission of the proton beams. The emission angle is closely related to the energy of the proton and the surface of the plasma target, the higher the energy the smaller the dispersion angle and the better the acceleration of the proton. The high speed of the accelerated protons would cause the better convergence of the beam. |
