Grad Shafronov equation

\[e=mc^{2}\] \[\text{this is a tes} \tag{1}\]

^3cef19

\(\frac{ \partial^{2} \psi }{ \partial r^{2} } -\frac{1}{r} \frac{ \partial \psi }{ \partial r } + \frac{ \partial^{2} \psi }{ \partial z^{2} } = -\mu_{0}r^{2} \frac{\text{d} p }{\text{d}\psi} - \frac{1}{2} \frac{\text{d} F^{2} }{\text{d}\psi} \tag{*}\) ^3de88a

[[ #^3cef19 ]]

[[ #^3de88a ]] this is a reference i hope works!

where: $\psi$ is the poloidal flux surface “label” $p(\psi)$ is the pressure $F(\psi)=rB_\theta$ $\frac{\text{d} F^{2} }{\text{d}\psi}$ is ff-prime or ff’


or from [[ Plasma II - APPH6102 ]]:

\[-\Delta^*\Psi=R^2\mu_0\frac{\partial p}{\partial \Psi}+F\frac{\partial F}{\partial \Psi}\]

where

  • the Stokes’ operator: $\equiv \frac{1}{R}\Delta^*\hat\phi=\frac{1}{R}\partial_z^2\Psi - \partial_R\left(\frac{1}{R}\partial_R\Psi \right)$
  • $F=RB_\phi=\frac{\mu_0I_{pol}}{2\pi}$
  • $F\frac{\partial F}{\partial \Psi}$ = FF’ (eff eff prime)
  • $\mathcal{L}[\Psi]=P(\Psi)+F(\Psi)$
  • in words, G-S is:
    • some operator (Stoke’s) operating on 2-D $\Psi$ (flux) function
    • =
    • 1-D poloidal function
    • +
    • 1-D flux function
  • what is $\Psi_{toroidal}$ (Zohm uses $\Phi$)? $\Psi_{poloidal}$?
    • $\Psi_T = \int B_\phi dS\approx B_\phi r^2$
      • $\phi$ points along axis of donut (toroidally)
      • often used as a “pseudo radius”, because $B_\phi$ is constant
    • $\Psi_P=\int B_\theta dS$
      • normalized poloidal flux; $\Psi_N$ = 0 at center, 1 at the edge
      • add constant so center is at 0, then scale to edge is =1
      • $\theta$ points around donut the short way

Shafronov shift

\[\frac{\partial \Delta}{\partial r}=-\frac{r}{R_0}\left( \hat \beta_p+\frac{\ell_i}{2} \right)\]

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