对飞秒激光等离子体相互作用中横向箍缩的观察

OBSERVATION OF THE TRANSVERSE PINCH OF THE EXPANSION OF AN FEMTOSECOND LASER-PLASMA

用飞秒激光的Normaski偏振干涉法 ,对超短激光脉冲产生的等离子体膨胀过程进行了光学诊断 ,得到了有时间分辨的等离子体干涉图 .发现飞秒激光等离子体在靶面平行的方向上出现了箍缩 ,使等离子体膨胀呈jet结构 ,这种箍缩现象是由自生磁场对等离子体的约束所造成 .

Using Normaski polarization interference technique, the expansion process of a plasma generated by ultrashort laser pulses was optically diagnosed. Temporal resolved interferogram of the laser\|plasma has been obtained. A strong pinch effect in the transverse dimension has been observed for a jet expansion of the laser\|plasma. It is found that the pinch effect was due to the confinement of the magnetic fields generated in the laser\|plasma.