The criterion for choosing between these three arrangements is established by the mass of the components and finally by the ratio of output power Pe to system mass. In the next section we shall establish approximate scaling relations for system component masses and evaluate specific power for each of the systems represented schematically in Figs. 4, 5 and 6. 4. Migma System Mass Estimates The power produced per unit reactor volume is proportional to ion density squared, and ion density, in turn, is proportional to the square of the vacuum magnetic field strength. Since the simulation that gave PO = 55.8 MW m-3 assumed a vacuum field of 10 Tesla, where p is the gyroradius of a 15 MeV proton (which must be contained in order to ignite) and the factor 3 takes into account expansion of the migma as diamagnetism reduces the central field to zero. In MKS units, /?=0.56/B. Thus the disc volume is
RkJQdWJsaXNoZXIy MTU5NjU0Mg==