In this paper we present a numerical study of plasma jets produced by intense laser matter interactions. Through this study we hope to better understand astrophysical jets and their recent experimental simulations in the laboratory. We paid special attention to radiation cooling and the interaction of the jet with ambient gas. Four cases are presented in this paper: two of them deal with the propagation of jets in the vacuum, while in the other two the propagation takes place in the ambient gas. Available experimental results are reproduced to good accuracy in the vacuum case. For jets in ambient gas, we find that the existence of the surrounding gas confines the jet into a narrow cylindrical shape so that both the density and temperature of the jet remain high enough for effective radiation cooling. As a result, a collimated plasma jet is formed in these cases. The dimensionless parameters characterizing the laboratory jets and protostellar jets have overlapping domains. We also discuss the cooling lengths for our model and compare them with the corresponding values in the astrophysical jets. A plasma jet in the ambient gas experiment is proposed which is within the reach of present-day technology and can be relevant to astrophysical phenomena.
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