A brief description is given of an axisymmetric mirror trap to demonstrate
ignition of a D-T plasma confined by ambipolar barriers. Key problems for t
his demonstration are ion pumping and suppression of instabilities in the t
hermal barriers. It is suggested that the fusion-fuel ions can be pumped aw
ay from the thermal barriers by exciting trapped-ion bounce oscillations at
parametric resonances. (C) 1999 American Institute of Physics. [S1063-7850
(99)00512-1].