A new method of focusing energy for the implosion of medium-speed liners (V ∼ 5 cm⋅μs−1) described. An attempt is made to show that the simplest method of achieving liner speeds in the range 1–10 cm⋅μs−1 is an impact of a fast plasma liner (V > 20 cm⋅μs−1) on a solid one. Such fast plasma liners can be produced in focused, Z-pinch-driven snowploughs. For this method of energy focusing and transfer to be applicable to a fusion reactor, gaseous, "inertial" electrodes rather than conventional metal ones must be used. The concept of a reactor based on these ideas is outlined.