Anomalous attenuation of laser light due to ion acoustic decay instability (IADI) in large scale plasma relevant to laser fusion

The IADI causes anomalous absorption of laser light with a moderate intensity laser in a large scale plasma. Because of the weak density modification due to the moderate intensity laser, the instability width can be large. The anomalous attenuation length of the laser can be much smaller than the instability width along the density gradient, indicating that most of laser energy may be anomalously absorbed by the IADI. An instability width of only a few laser wavelengths is sufficient to absorb most of the laser energy. Experimental results are consistent with the large scale plasma and the strong absorption.