Temperature relaxation in hot spots in a laser-produced plasma

P.N. Lebedev Physics Institute, Russian Academy of Sciences, Moscow 117924, Russia~Received 31 July 1997!The study of temperature relaxation and ion acoustic wave excitation in localized regions of intense laserfield~hot spots! has been carried out for the conditions of inhibited electron thermal transport. We consider thefast energy deposition in a single cylindrical hot spot and describe the following temperature and densityrelaxation using a perturbation approach and the nonlocal electron transport equations. We find a significantincrease in the temperature relaxation time for hot spots with sizes comparable to the electron mean free path.Thermal decay of the hot spot together with the pondermotive effect of the laser field on ions could also be asource of large density fluctuations in currently exploited laser-produced plasmas. @S1063-651X~97!06312-5#PACS number~s!: 52.40.Nk, 52.35.Mw, 52.35.NxI. INTRODUCTION