Model for divertor function in H-mode onset and proposal for H-mode operation with the island divertor

We propose that the main function of the divertor configuration in the H-mode mechanism is temporary storage of the effluxing particles for a time longer than the edge energy confinement time. This temporary storage enables the edge temperature to transiently increase above a threshold temperature necessary for the H-mode transition. This model qualitatively explains the superior H-mode regime in mechanically closed poloidal divertors and opens the possibility that the same result could be achieved using the resonant island divertor