Noncontact thermal gradient method for fabrication of uniform cryogenic inertial fusion target

A new method for fabricating a uniform layer of fuel condensate inside a spherical-shell inertial confinement fusion target is described. In this method, target cooling is done in a vertically imposed temperature gradient whose magnitude is continuously controlled until the thermally induced effects precisely counterbalance the gravity effect. As a consequence, gravity-induced fuel sagging is completely eliminated resulting in the formation of a uniform fuel-condensate layer on the inner surface of the target. Since the present method is immune to the gravity effect, it is uniquely qualified for fabricating targets containing a thick fuel layer— an important capability no other existing method possesses. A brief description of the experimental methods and the preliminary results showing the promise of the new method are presented.