Close but with some important differences. We've tried that approach and it has some interesting potential applications but, when it comes to building a power plant that has to last decades, we think the engineering is just too difficult. Instead of pushing on a liner that then pushes on the plasma, we directly push on the plasma with magnetic field. The engineering, while still difficult, is much easier to tackle.

Is this a purely magnetic approach? I recall recently reading about a MagLIF variant that used lasers for pre-heating.

It is. We use electromagnets to make the plasmas, move them, and finally compress them all without moving parts, just magnetic field.