1. Studies on subcritical and overcritical density laser ablated TAC foam targets
- Author
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A. Orekhov, Shivanand Chaurasia, D.S. Munda, P. Leshma, C. G. Murali, A. I. Gromov, L. J. Dhareshwar, N.G. Borisenko, and Yu.A. Merkuliev
- Subjects
Yield (engineering) ,Materials science ,business.industry ,engineering.material ,Shadowgraphy ,Laser ,Molecular physics ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Shock (mechanics) ,law.invention ,Optics ,Coating ,law ,engineering ,Supersonic speed ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,business ,Absorption (electromagnetic radiation) ,FOIL method - Abstract
In this paper, the interaction of high power laser with low density polymer foam with density as low as 2 mg/cm 3 , 4 mg/cm 3 , 20 mg/cm 3 30 mg/cm 3 and 50 mg/cm 3 targets are investigated and compared with solid polymer targets. An understanding of such interaction is important from fusion research point of view. Low density foam coating of fusion capsule has been proposed in order to smooth in direct drive scheme and also it is being used as efficient x-ray converter in indirect drive scheme. It is observed that about 75–80% of the laser energy is absorbed in the subcritical (with density 3 ) foam targets and the soft x-ray yield in this case is almost two times that measured in the over dense (supper critical) targets. The optical shadowgraphy of the targets shows that the laser coupling in low density foam is associated with a supersonic heat wave while, with increasing density this phenomenon is replaced by subsonic absorption and shock formation. In the case of a 50 mg/cm 3 foams the foil velocity reduced by 35% (i.e. 5×10 6 cm/s), which further reduced to 3.8×10 6 cm/s in case solid polymer targets.
- Published
- 2015