FIREX: Field-Reversed Ion Ring Experiment
W.J. Podulka,
J.B. Greenly, Yu.A. Omelchenko, R.N. Sudan (Cornell Univ., Ithaca, NY)
FIREX is intended as a major step toward the realization of a field-reversed Ion Ring
or Ion Ring/FRC reactor in which large orbit ions provide MHD stability to a
high-\beta field-reversed configuration. The goal of FIREX is to produce a fully
field-reversed ring with \sim 1 MeV protons. The proton beam is generated by a pulser
which will deliver a 1.2 MV, 800 kA, 150 ns pulse at full power to a
magnetically-insulated ion diode of annular extraction geometry with 500 cm^2 area,
designed to operate at 1.5 kA/cm^2 ion current density. The beam is injected through
an axially compact magnetic cusp into a gradual ramped solenoidal magnetic field,
which rises from 6 to 9 kG over 2 m axial length. FIREX has now operated well at 70%
charge, giving nearly full voltage at 800 A/cm^2 current density, and is now
proceeding toward full power operation. Results of beam injection and ring formation
will be presented and compared with numerical simulations. Several basic features of
ring and background plasma dynamics predicted in simulations have already been
observed in the experiment. We believe that the present results will scale
successfully to field-reversed rings at full power.