Magnetohydrodynamic Stability at a Separatrix: Part II
| dc.creator | Webster, A. J. | |
| dc.date | 2009-02-20 | |
| dc.date.accessioned | 2026-07-07T12:45:03Z | |
| dc.date.available | 2026-07-07T12:45:03Z | |
| dc.description | In the first part to this paper\cite{part1} it was shown how a simple Magnetohydrodynamic model could be used to determine the stability of a Tokamak plasma's edge to a Peeling (External Kink) mode. Stability was found to be determined by the value of $Δ'$, a normalised measure of the discontinuity in the radial derivative of the radial perturbation to the magnetic field at the plasma-vacuum interface. Here we calculate $Δ'$, but in a way that avoids the numerical divergences that can arise near a separatrice's X-point. This is accomplished by showing how the method of conformal transformations may be generalised to allow their application to systems with a non-zero boundary condition, and using the technique to obtain analytic expressions for both the vacuum energy and $Δ'$. A conformal transformation is used again to obtain an equilibrium vacuum field surrounding a plasma with a separatrix. This allows the subsequent evaluation of the vacuum energy and $Δ'$. For a plasma-vacuum boundary that approximates a separatrix, the growth rate $γ$ normalised by the Aflven frequency $γ_A$ is then found to have $\ln(γ/γ_A)=-{1/2} \ln (q'/q)$. Consequences for Peeling mode stability are discussed. | |
| dc.description | 1 figure | |
| dc.identifier | https://arxiv.org/abs/0902.3587 | |
| dc.identifier | http://arxiv.org/abs/0902.3587 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/220973 | |
| dc.subject | Plasma Physics | |
| dc.title | Magnetohydrodynamic Stability at a Separatrix: Part II | |
| dc.type | text |