Research On The Expansion Dynamics Of Laser-induced Plasma Under Magnetic Field Confinement

Confinement by magnetic field is used to constrain the movement of the plasma charged particles in the field, the plasma confinement in a certain area. Avoid the spread of technology. It is widely used in laser-induced breakdown spectroscopy, magnetic confinement fusion technology, lithography technology and magnetron sputtering technology, researchers have been of great concern to all countries. Due to its physical process is very complex, so we need research magnetic field under the constraint of the laser-induced plasma expansion dynamics of in-depth.The thesis studies the behavior of microscopic particles of plasma magnetic field constraints, the physical process of plasma plume expansion body shape, plasma shock wave expansion processes.Under the established field of laser-induced plasma atomic emission spectrometry constrained experimental system and optimize the experimental conditions, the final results showed that the magnetic field within the constraint of copper plasma atomic spectroscopy and ion spectra were all enhanced.Investigation on the spatial and temporal evolution of the plasma, combined with the electron temperature, electron density, and the different nature of the target, the laser excitation pulse energy obtained from the electrons through magnetic Joule heating energy, increased risk of collision, the electron-ion recombination rate of increase in the three aspects of the magnetic field constraints enhanced plasma emission spectroscopy explained. The physical reason for the magnetic field strength of the confined plasma enhanced emission spectra were discussed.Observation by flash photography method to a particular time of the plasma plume inside the disorder, in a small area near the target, the plasma plume inside temperature is higher than elsewhere. And this time, and plasma emission spectroscopy nodes can occur during the time evolution of bimodal structure echoes, further validates the enhanced spectral interpretation. Such as the post-expansion becomes elongated body shape ion plume, plasma shock wave through the images we see, the plasma inside volatility, it can be inferred high electron density within the signal region, and in the same area before the rapid plasma photography reflected in diameter to compress the same. Verify that the MHD instabilities caused by the above results.