Control of ash accumulation by induced-fishbones

Thermal alphas will accumulate in the ignited long pulse tokamak. Ash accumulation results in fuel dilution, reduced power output, increase in Zeff, and increased synchrotron losses. Recent 'Baldur' simulations of the ITER show that the ash accumulation is a distinct possibility for high ash recycling case, inevitably leading to burn quench. So, some means of ash is highly desirable. To this end, several control schemes have been looked at. Given the uncertainty in transport information especially for the ash and other impurity transport, it is desirable to incorporate some explicit ash control features in the tokamak design. Continuing the search for more desirable schemes, in this paper we explore the effectiveness of 'fishbones' towards controlling the alpha accumulation