CAJ | 학술논문

基于等离子体荧光法研究了Nd∶YAG纳秒1064 nm激光脉冲诱导击穿空气等离子体的膨胀动力学过程，用ICCD相机捕获了不同激光脉冲能量诱导的空气等离子体随时间演化图像，给出激光能量100，150，200，300 m J时击穿空气产生的空气等离子体波阵面前沿的膨胀距离，推演出空气等离子体的扩展速度。实验结果表明等离子体发光区域主要分布在等离子体膨胀区域，等离子体荧光强度随时间增加变强然后渐渐变弱，膨胀区域逐渐增大，在300 mJ ，22 ns膨胀距离最大达到3.76 mm ，等离子体扩展速度在膨胀初期达到105 m · s-1量级，在膨胀16 ns内迅速衰减，随后趋于平缓。激光脉冲能量越大，引起空气击穿的时刻靠近高斯激光脉冲上升阶段。
기우등리자체형광법연구료Nd∶YAG납초1064 nm격광맥충유도격천공기등리자체적팽창동역학과정，용ICCD상궤포획료불동격광맥충능량유도적공기등리자체수시간연화도상，급출격광능량100，150，200，300 m J시격천공기산생적공기등리자체파진면전연적팽창거리，추연출공기등리자체적확전속도。실험결과표명등리자체발광구역주요분포재등리자체팽창구역，등리자체형광강도수시간증가변강연후점점변약，팽창구역축점증대，재300 mJ ，22 ns팽창거리최대체도3.76 mm ，등리자체확전속도재팽창초기체도105 m · s-1량급，재팽창16 ns내신속쇠감，수후추우평완。격광맥충능량월대，인기공기격천적시각고근고사격광맥충상승계단。
The expansion dynamics of air plasma induced by 1 064 nm nanosecond laser pulse was studied by plasma fluorescence method .The time evolution images of air plasma expansion were acquired using the ICCD camera at different laser pulse energy , and the expansion velocity of air plasma was deduced based on the air plasma frontier expansion wave front distance at 150 mJ . The experimental results show that the plasma fluorescence was mainly distributed in the plasma expansion region ,the plasma fluorescence intensity firstly increased then became weaker and the expansion area increased gradually with time evolution ,.The biggest expansion distance was 3.76 mm with 300 mJ at 20 ns .The plasma expansion speed was the order of magnitude of 105 m · s-1 at the early stage of expansion process .The expansion speed of air plasma decayed rapidly within 16ns ,then changed slowly with time .The time of air breakdown was close to the rising phase of laser pulse when the greater laser pulse energy was radiated .