16.7 Double transport barriers pressure profile

An analytic expression for the pressure profile of double (inner and external) transport barriers is given by

         (        ( − (ψ − ψ )) )   (       ( − (ψ − ψ )))
P (ψ) = ai 1+ tanh  -------i-   +ae  1+ tanh  -------e-   − c
                       wi                        we
(501)

where ψ is the normalized poloidal flux, wi and we are the width of the inner and external barriers,  ψi and ψe are the locations of the barriers, ai and ae is the height of the barriers, c is a constant to ensure P(ψ) = 0 at ψ = 1.


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Fig. 36: Pressure profile of double (inner and external) transport barriers given by Eq. (501) with ai = 1, bi = 0.2, ψi = 0.36, ψe = 0.96, wi = 0.2, we = 0.04, c = 0.

 


pict

Fig. 37: Equilibrium pressure profile for EAST discharge #38300 at 3.9s (reconstructed by EFIT code, gfile name: g038300.03900), which shows a boundary transport barrier.