Profile constraining mechanism for T{sub e} profile invariance in tokamaks Becker, G 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; TOKAMAK DEVICES; ELECTRON TEMPERATURE; THERMAL DIFFUSIVITY; ELECTRONS; ELECTRON DENSITY; SCALING LAWS; SPATIAL DISTRIBUTION; JOULE HEATING; 700410; SPECIFIC FUSION DEVICES AND EXPERIMENTS A new model for the electron temperature profile resilience in the outer half of tokamak plasmas is proposed and investigated. It is shown that introducing a negative feedback term into the scaling of the electron heat diffusivity {chi}{sub e}(r) = {chi}{sub ee}(r)(1-{alpha}a{sup 2}/T{sub eo} d{sup 2}T{sub e}/dr{sup 2}) with {alpha} > or {approx} 3 results in the observed T{sub e} profile stiffness against variations of the density and heating profiles. In addition, the feedback by itself yields the measured approximately linear T{sub e}(r) shape for r/a > or {approx} 0.5 in contrast to previous profile constraining models. (orig.). 6 figs. Max-Planck-Institut fuer Plasmaphysik, Garching (Germany) OSTI; NTIS (US Sales Only); INIS Germany 1993-03-01 English Technical Report Other Information: PBD: Mar 1993 Medium: X; Size: 14 p. https://doi.org/ ON: DE94733999 [] IPP-5/51 Other: ON: DE94733999; TRN: DE94F0658 DEN; SCA: 700410; PA: DEN-94:0F0658; EDB-94:027907; ERA-19:007878; NTS-94:015644; SN: 94001136105 2008-02-12 10119781