Wave Propagation amd Transport Phenomenon in controlled Fusion

Abstract

In the project under consideration, which was for a period of three years, we have dealt with the following problems. i) The dynamics of a finite-thickness gas-puff Z — 0 pinch producing a high density plasma was investigated and studied numerically. The results obtained by modifying the codes of earlier work have been published in an international journal (see copy attached). Considering the effect of Ohmic heating with adiabatic conditions and incorporating the radiation losses, fusion conditions were studied for a finite-thickness gas-puff staged Z-pinch. The results of this study have been accepted for publication (see copy attached). An important observation was made that a relatively thick puff layer will be useful to obtain parameters like density and temperature with enhanced stability in the acceleration phase of puff layer in contrast with the theoretical observations of the previous work advocating thin puff layer. The numerical results we have obtained predict stability and will be very helpful in future experimental work on Z — 0 pinch device in our plasma laboratory. ii) Regarding work on laser-induced plasma, an analytical nonlocal heat transport formula based on the reduced Fokker-Planck equation was considered. The effects of inverse-bremsstrahlung absorption as well as the electrostatic po- 9tential on heat flux for a strongly inhomogeneous plasma were investigated. It was found that while the former contributes an additive term to the heat flux enhancing its value for both steep and gentle gradient situations; the latter effect introduces an exponential term which significantly reduces the electron thermal transport. Our calculations also showed that for a moderately intense laser field, the maximum heat flux for steep gradient situations corresponds to flux inhibition factor of the order of 0.17. This work has also been published (see Copy attached). iii) Experimental work on sequential focusing in a. Mather-type Plasma Focus has been carried out. The results indicate that such a device can possibly be used as a •cascading focus deviCe to produce bursts of neutrons and soft xrays. This work has been published in a journal of international repute (see copy attached).