France has upped the ante in the quest for fusion power by maintaining a plasma reaction for over 22 minutes – a new record. The milestone was reached on February 12 at the Commissariat à l'énergie atomique et aux énergies alternatives (CEA) WEST Tokamak reactor.
I think this energy density math really depends on whether only the core or the whole surface area is taken into consideration.
Even the core only has an output of 200-300W/m^3.
That’s about the energy output per volume of a 70 year old cyclist.