On the possibility of target plasma ignition under the conditions of inertial nuclear fusion

The thermonuclear gain G for bulk and spark ignitions are calculated using a mathematical simulation of thermonuclear combustion in a DT plasma of las er targets for various parameters of the target plasma and (isobaric and is ochoric) ignitors. The critical parameters of ignitors at which an effectiv e nuclear burst occurs with G similar to 100 are calculated. It is shown th at a further increase in the temperature and size of the ignitors virtually does not affect the efficiency of DT fuel burnup. Irrespective of the igni tion technique, the value of G can be estimated with the help of a simple a smptotic formula. At the same time, the critical parameters of ignitors are determined to a considerable extent by the mode of ignition and by the tar get parameters. Spark ignition with an isochoric ignitor corresponding to t he fast ignition mode is considered in detail. It is shown that the main cr itical parameter for optimal isochoric ignitors is their thermal energy lib erated upon absorption of an auxiliary ultrashort laser pulse. The critical values of this energy are calculated. (C) 2001 MAIK "Nauka/Interperiodica" .