Amending the reflected shock phase of the Lee code

The radial reflected shock phase begins when the inward shock front (IS) which is collisional hits the central axis and a reflected shock (RS) is produced that moves radially outward. This phase ends and the pinch phase begins when the outward moving RS front meets the inward moving magnetic piston. The Lee code approximates the RS phase by taking an estimated constant RS speed in the formulation of the code. In this paper we analyse the RS situation in more detail. A physical mechanism is used to obtain the RS speed as functions of position and time during its propagation towards the incoming piston. This is an important amendment to this phase of the code. In computing the RS speed, the temperature variation during the RS phase is also obtained. The speed and temperature versus time profiles are presented demonstrating a more realistic picture than the constant speed and temperature assumption. The temperature-radius profile across the pinch at its start is also derived.