MHD equilibrium: Difference between revisions

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Since the field line trajectories are described by Hamiltonian equations, the [[:Wikipedia:Kolmogorov-Arnold-Moser_theorem|KAM theorem]] is relevant.
Since the field line trajectories are described by Hamiltonian equations, the [[:Wikipedia:Kolmogorov-Arnold-Moser_theorem|KAM theorem]] is relevant.


It should be noted that the force balance equation does not describe any detail on scales smaller than the gyroradius. Therefore, the concept of flux surface is approximate and not exact.
It should be noted that the force balance equation does not describe any detail on scales smaller than the gyroradius. In combination with the existence of stochastic field regions this means that the concept of flux surface can only be approximate and not exact.
Nevertheless, it is extremely useful for the description and understanding of magnetic confinement.
Furthermore, the force balance equation depends on a number of assumptions, such as that of static equilibrium, whereas fusion-grade plasmas are clearly strongly driven systems far form equilibrium.
Nevertheless, ideal MHD equilibrium is extremely useful for the description and understanding of magnetically confined plasmas.


== Numerical codes ==
== Numerical codes ==