#
53rd Annual Meeting of the APS Division of Plasma Physics

## Volume 56, Number 16

##
Monday–Friday, November 14–18, 2011;
Salt Lake City, Utah

### Session CI2: Pedestal Control With 3D Fields

2:00 PM–5:00 PM,
Monday, November 14, 2011

Room: Ballroom BD

Chair: Jon Menard, Princeton Plasma Physics Laboratory

Abstract ID: BAPS.2011.DPP.CI2.6

### Abstract: CI2.00006 : Effect of Resonant Magnetic Perturbations on secondary structures in Drift-Wave turbulence*

4:30 PM–5:00 PM

Preview Abstract
Abstract

####
Author:

Michael Leconte

(NFRI)

In this work, we study the effects of RMPs on turbulence, flows
and confinement, in the framework of two paradigmatic models,
resistive ballooning and resistive drift waves.
For resistive ballooning turbulence, we use 3D global numerical
simulations, including RMP fields and (externally-imposed)
sheared rotation profile. Without RMPs, relaxation oscillations
of the pressure profile occur.
With RMPs, results show that long-lived convection cells are
generated by the combined effects of pressure modulation and
toroidal curvature coupling. These modify the global structure of
the turbulence and eliminate relaxation oscillations.
This effect is due mainly to a modification of the pressure
profile linked to the presence of residual magnetic island
chains. Hence convection-cell generation increases for increasing
$\frac{\delta B_r}{B_0}$.
For RMP effect on zonal flows in drift wave turbulence, we extend
the Hasegawa-Wakatani model to include RMP fields.
The effect of the RMPs is to induce a linear coupling between the
zonal electric field and the zonal density gradient, which drives
the system to a state of electron radial force balance for large
$\frac{\delta B_r}{B_0}$.
Both the vorticity flux (Reynolds stress), and particle flux are
modulated. We derive an extended predator prey model which
couples zonal potential and density dynamics to the evolution of
turbulence intensity.
This model has both turbulence drive and RMP amplitude as control
parameters, and predicts a novel type of transport bifurcation in
the presence of RMPs.
We find a novel set of system states that are similar to the
Hmode-like state of the standard predator-prey model, but for
which the power threshold is now a function of the RMP strength. For
small RMP amplitude and low collisionality, both the ambient
turbulence and zonal flow energy increase with $\frac{\delta
B_r}{B_0}$.
For larger RMP strength, the turbulence energy increases, but the
energy of zonal flows decreases with $\frac{\delta B_r}{B_0}$,
corresponding to a damping of zonal flows. At high
collisionnality, zonal flow damping occurs even at small RMP
amplitude. Finally, for very strong values of $\frac{\delta
B_r}{B_0}$, the system bifurcates back to an Lmode-like state.

*This work was supported by the World Class Institute (WCI) Program of the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology of Korea (MEST).

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.DPP.CI2.6