A new laser fusion target concept is presented with a predicted energy gain
of 127 using a 1.3 MJ KrF laser. This energy gain is sufficiently high for
an economically attractive fusion reactor. X rays from high- and low-Z mat
erials are used in combination with a low-opacity ablator to spatially tune
the isentrope, thereby providing both high fuel compression and a reductio
n of the ablative Rayleigh-Taylor instability. (C) 2000 American Institute
of Physics. [S1070-664X(00)04505-5].