Resonant Magnetic Perturbation: Difference between revisions

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-RMP (Resonant Magnetic Perturbations)
+A Resonant Magnetic Perturbation (RMP) is an externally-induced small perturbation of the [[MHD equilibrium|equilibrium]] magnetic field,
+such that it is resonant with the field at a given magnetic [[flux surface]],
+usually located in the plasma edge region.
+Resonance means that the perturbation has the same [[Rotational transform|helicity]] as the equilibrium magnetic field at the target flux surface.
+The perturbation is assumed to lead to the ergodization of the magnetic field around the resonant flux surface.
-$Definition$
+The goal is to stabilize a specific instability, mainly [[Edge Localized Modes]] (ELMs), in order to reduce the deleterious effects of the corresponding transport bursts on the wall of the device.
-A Resonant Magnetic Perturbation (RMP) is an externally-induced small perturbation of the equilibrium magnetic field,
+<ref>[[doi:10.1038/nphys312|T.E. Evans, et al, ''Edge stability and transport control with resonant magnetic perturbations in collisionless tokamak plasmas'', Nature Physics '''2''' (2006) 419 - 423]]</ref>
-that is resonant with it, i.e. it has the same helicity as the equilibrium magnetic field, on a given magnetic flux surface,
+Resonance of the externally imposed field with the field line pitch is assumed to be essential for the generation of a stochastic zone and the desired mitigating effect on the instability.
-usually designed to be located in the plasma edge region.
+<ref>[[doi:10.1103/PhysRevLett.103.165005|O. Schmitz, T.E. Evans, M.E. Fenstermacher, et al, ''Resonant Pedestal Pressure Reduction Induced by a Thermal Transport Enhancement due to Stochastic Magnetic Boundary Layers in High Temperature Plasmas'', Phys. Rev. Lett. '''103''' (2009) 165005]]</ref>
+However, recent results indicate that resonance is not strictly necessary to obtain a mitigating effect on ELMs from external field perturbations.
+<ref>[[doi:10.1103/PhysRevLett.106.225004|W. Suttrop, T. Eich, J.C. Fuchs, et al, ''First Observation of Edge Localized Modes Mitigation with Resonant and Nonresonant Magnetic Perturbations in ASDEX Upgrade'', Phys. Rev. Lett. '''106''' (2011) 225004]]</ref>
+== References ==
+<references/>