In laser-fusion experiments, the degree of preheating of the thermonuclear fuel and of the imploding shell that compresses the fuel is an important factor determining the efficiency of fuel compression. Results are presented here of fast-electron-, radiation-, and shock-wave-induced preheating in the laser-driven thermonuclear fusion experiments with high-aspect-ratio shells at the laser intensity ${10}^{14}$ W/${\mathrm{cm}}^2$. An alternative technique is proposed for the measurement of fast-electron-induced preheating. The technique is based on analysis of superthermal plasma x-ray radiation. The roles of radiation and shock-wave-induced preheating are also evaluated.

• Received 18 April 1990

DOI:https://doi.org/10.1103/PhysRevA.43.3024