EMPIRICAL SCALING LAWS FOR ENERGY CONFINEMENT IN OHMICALLY-HEATED TOKAMAKS

The interpretation and empirical determination of scaling laws for tokamak energy confinement are discussed. Special emphasis is given to the difficulty in determining the temperature dependence of the confinement time from Ohmically-heated data. A large collection of Ohmically-heated data is then presented. These data are analysed statistically to obtain the following temperature and confinement time scalings: ⟨Te⟩=e−9.3⟨ne⟩−0.10a−1.29R0.66I0.88≡ Π and ΤEe = e−43.8⟨ne⟩0.90a0.98R1.63(⟨Te⟩/Π)γ. The exponent γ is undetermined, and the units are mks and keV. If the confinement time is assumed independent of temperature and if dimensional constraints are imposed, then the best scaling becomes ΤEe = e−47.5 ⟨ne⟩ a5/4 R. These scalings are compared to several previously proposed ones. © 1979 IOP Publishing Ltd.