Comparison between surface recession of boron pebble aggregates due to laser heating and DIII-D divertor heat loads

First DIII-D divertor exposures of boron pebble aggregates with a single carbon-based binder composition show consistent recession rates in L-mode (~1 mm/s) and H-mode (~2 mm/s), comparable to laser heat tests at 40 MW/m². Boron pebble aggregates are renewable materials of interest for magnetic fusion reactor divertors, combining high heat load handling and slag recovery with good core performance. Laser heating tests show handling up to 40 MW/m² via controlled surface recession at 1-2 mm/s, with recession rates tunable through inter-pebble binder content and composition. Pebbles are generally recovered without melting when binder is optimized for the target heat load. Some pebble melting was observed in the DIII-D tests, indicating carbon binder was not optimally tuned for the divertor conditions. Preliminary analysis indicates pebble ejection predominantly along incoming heat flux direction in both, laser heating and plasma experiments. Poor pebble recovery in the 5 cm diameter region of the divertor suggests ejected pebbles are swept from the strike point region, with implications in the design of pebble recovery systems in a reactor. Dust emission was observed, presumably from the inter-pebble binder. Boron uptake into core plasma occurred without negative effects on core performance.