Control of thermal instability of pure and catalyzed D-D fusion reactor plasmas.

Abstract

The possibility eliminating the thermal instability of self-sustained pure and catalyzed D-D fusion reactor plasmas is examined, using the two feedback models of (a) fueling rate and (b) power control (control by power injection or subtraction). Calculations are performed on the bases of linear stability analysis and non-linear dynamic simulation. In contrast to D-T fusion plasma, Cat. D plasma can be stabilized by fueling rate control in all the confinement time scalings adopted in the study. Pure D plasma is not completely stabilized by fueling rate control except when the confinement times are governed by trapped-ion mode (TIM) scaling. The plasma, however, can be maintained near equilibrium state even in forms of scaling other than TIM. Among the different types of fueling rate control, the one most suitable would appear to be deuterium control, in which the rate of deuterium injection is increased [decreased] to counteract temperature increase [decreased]. With power control, temperature increase [decrease] is counteracted by subtraction [addition] of power out of [into] the plasma. Compared with fueling rate control, this method exerts a more direct effect, although it involves a more complex procedure.