Abstract The gaps between divertor tiles are ideal hideouts of impurities. To investigate the impurity deposition in the gaps, one needs to understand the plasma behavior well. This work employs a 2d3v PIC-MCC model to study the plasma characteristics inside and outside the tile gap. Under such plasma conditions from the simulation, the energy fluxes to the tile surfaces are obtained and the erosion rates of carbon-based tile plates are further evaluated. In addition, effects of magnetic field strength on the energy flux are also discussed.