The particle end losses from a linear magnetic fusion reactor can be suppressed by establishing an ablation front in a cold gas blanket. The power density W(W/cm2) to drive the thermal front may be drawn from inside (energy end losses) or outside (auxiliary heating). With W below 109 W/cm2 and a D–T blanket the particle outflow is retarded. With higher W values the flow is completely stopped and the fusion plasma is recompressed by a shock wave traveling inwards from the ends.