During hard disruptions, dangerous overheating of the limiter can be avoided if it is protected by a dense, cold, high-Z plasma blanket - the "virtual limiter", as it has been termed throughout the present paper. The virtual limiter intercepts the particles escaping from the hot plasma core, and radiates away the absorbed energy as a flux of soft X-rays. The physics of such a process is investigated in the present paper, and specifications are derived for the achievement of effective protection.