高功率片状放大器在线运行时氙灯辐照导致片腔内产生大量气溶胶，易引起钕玻璃污染，影响其使用寿命。采用洁净氮气吹扫恢复片腔内的洁净环境是片状放大器在线运行时的主要洁净手段。研究了氮气吹扫过程中片腔内涡流对洁净度的影响，结果显示涡流对气溶胶颗粒的禁锢作用会导致腔内气溶胶颗粒的大量残留，且无法通过延长吹扫时间或调整吹扫流速加以解决。针对这一问题，提出了间断多次氮气吹扫对腔内气溶胶进行循环稀释的在线洁净控制方法，该方法使腔内涡流经历不断破坏和重建过程，涡流场内滞留的气溶胶颗粒含量也得到不断稀释，从而大幅提高片腔洁净度。针对Φ130 mm单口径片状放大器进行了对比实验研究。采用间断吹扫法之后，腔内残留气溶胶颗粒为连续吹扫时的1/100，片腔洁净度在15 h的观测时间内始终保持在40级以内。该方法普适有效，为避免片状放大器钕玻璃气溶胶污染,增加其在线使用寿命提供了重要参考。

While the disk amplifier is operated, the aerosols originating from the decomposition of organic material exposed to flash lamp light is inevitable, which can cause the disk contamination and damage consequently. The nitrogen gas purging is routinely employed to re-achieve the slab cavity cleanliness, which is fundamentally required for disk amplifier reliable performance. The influence on aerosol dissipation by swirl is measured, demonstrating that the desirable cleanliness can not be achieved simply by prolonging the purging time or adjusting the flowing rate as plenty of aerosol is slaved in swirl. So we propose the aerosol dissipation by intermittent purging. The decaying of aerosol concentration is achieved rapidly by repeated dilution as the swirl is destructed time after time. The comparative experiment is carried out at a Φ130 mm disk amplifier specially. After intermittent purging, the residual aerosol concentration in slab cavity is 1/100 of that after a continuous but longer purging. The slab cavity environment cleanliness remains lower than level 40 in the following 15 h, which is much more desirable to prevent neodymium glass from contamination and damage.