Magnetic Field Compression By Intense-laser-driven Relativistic Thin Layer

As an extreme physical condition,high magnetic fields generated in the laboratory have greatly promoted the development of scientific research on astrophysics,plasma physics,material physics,quantum electrodynamics,and the generation of gamma-ray and pairs.Therefore,the research on high magnetic field generation is of great significance.Magnetic field compression technique is a very effective and practical way to generate high magnetic fields.Generally,chemical implosion compression and electromagnetic flux compression can be used to generate a high magnetic field.However,the low energy conversion efficiency and the asymmetry of implosion make the magnetic field generated by electromagnetic magnetic flux compression only reach a few hundred Tesla.Usually,the compression speed of the magnetic field compression method is slow and the seed magnetic field is small.Thus,this thesis proposes a new method of compressing magnetic field by using relativistic thin layers,which can be produced by laser plasma interactions.The method can speed up the compression of seed magnetic field and the magnitude of the pre-seeding magnetic field can be very high.The main work of this thesis is as follows:1 Use relativistic electron layers driven by intense laser pulses to compresses magnetic fields.Under the compression of the relativistic electron layer,the intensity of the seed magnetic field is increased tenfold.Moreover,Particle in cell(PIC)simulations show that if the peak power of the incident laser and the initial plasma density both increase,then the magnetic field obtained become higher.2 Use relativistic plasma layers driven by intense laser pulses to compresses magnetic fields.During the compression process,the part of the laser energy is converted from high-energy ions to magnetic energy,but the magnetic flux remains conserved.When the magnetic field is compressed and amplified,it generates an electric field of the corresponding magnitude.The magnetic field is perturbed at the speed of light and propagates in the form of electromagnetic waves.The simulation shows that an initial 10⁴ T magnetic field can be compressed and amplified to 10⁷ T(the corresponding intensity is 10²⁴ W/cm²),which implies 3 orders of magnitude increase for the amplitude of the magnetic field.Relativistic thin layers driven by intense laser can compresses and amplify a seed magnetic field,leading to a super high magnetic field.Such a high magnetic field can be used to study some phenomena in the field of quantum electrodynamics in the laboratory.