Studies of ultra-intense laser plasma interactions for fast ignition

Laser plasma interactions in a relativistic parameter regime have been inte nsively investigated for studying the possibility of fast ignition in inert ial confinement fusion (ICF). Using ultra-intense laser systems and particl e-in-cell (PIC) simulation codes, relativistic laser light self-focusing, s uper hot electrons, ions, and neutron production, are studied. The experime nts are performed with ultra-intense laser with 50 J energy, 0.5-1 ps pulse at 1053 nm laser wavelength at a laser intensity of 10(19) W/cm(2). Most o f the laser shots are studied under preformed plasma conditions with a 100 mu m plasma scale length condition. In the study of laser pulse behavior in the preformed plasmas, a special mode has been observed which penetrated t he preformed plasma all the way very close to the original planar target su rface. On these shots, super hot electrons have been observed with its ener gy peak exceeding 1 MeV. The energy transport of the hot electrons has been studied with making use of K alpha emissions from a seeded metal layer in planar targets. The details of ion acceleration followed by beam fusion rea ction have been studied with neutron spectrometers. Laser ponderomotive for ce self-focusing and hot electron generation have been applied to a compres sed core to see the effect of heating by injecting 12 beams of 100 ps, 1 TW pulses. (C) 2000 American Institute of Physics. [S1070-664X(00)95605-2].