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In the process of laser propagation, the wavefront distortion and wave breaking of target laser may be caused by the
impact of transmission environment, resulting in that the actual target spot appears the change of spatial and temporal
distribution. It is built a numerical simulation model of millisecond pulse laser interaction with material by COMSOL
Multiphysics software and a contrastive analysis is made on the temperature distribution differences of alumina under the
effect of actual target laser and ideal Gaussian laser respectively. And the study shows that the temperature of alumina
raises with the increase of energy and obvious deposition on the surface of temperature by laser irradiation. Moreover,
temperature difference exists inside laser irradiation area due to the gradient difference appearing in the spatial
distribution of laser energy during the interaction between laser and alumina. As a result, the energy transfer from
high-temperature area to low-temperature area, following by the temperatures of two adjacent areas to affect each other.
When analyzing the actual target laser, the spatial distribution of temperature field is consistent with the stray spots in
general though, they are slightly different with in local area. Such local difference is determined by the heat transfer
coefficient of alumina materials and energy distribution gradient of beam spot together. When the energy of actual target
laser is greater, the difference between temperature field and the spatial distribution is more obvious. Since the energy of
actual target laser has a significant gradient difference with that of Gaussian laser, its interaction with alumina also shows
an obvious difference in temperature distribution. Therefore, not all incident lasers can be idealized as the standard beam
spot. The results have guiding significance in improving the application of laser processing quality in terms of
long-distance transmission.
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