skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A reduced resistive wall mode kinetic stability model for disruption forecasting

Authors:
 [1];  [1];  [2];  [2];  [2]
  1. Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
  2. Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543, USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1348023
Grant/Contract Number:
AC02-09CH11466; FG02-99-ER54524
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 5; Related Information: CHORUS Timestamp: 2018-02-14 23:56:29; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics
Country of Publication:
United States
Language:
English

Citation Formats

Berkery, J. W., Sabbagh, S. A., Bell, R. E., Gerhardt, S. P., and LeBlanc, B. P. A reduced resistive wall mode kinetic stability model for disruption forecasting. United States: N. p., 2017. Web. doi:10.1063/1.4977464.
Berkery, J. W., Sabbagh, S. A., Bell, R. E., Gerhardt, S. P., & LeBlanc, B. P. A reduced resistive wall mode kinetic stability model for disruption forecasting. United States. doi:10.1063/1.4977464.
Berkery, J. W., Sabbagh, S. A., Bell, R. E., Gerhardt, S. P., and LeBlanc, B. P. Mon . "A reduced resistive wall mode kinetic stability model for disruption forecasting". United States. doi:10.1063/1.4977464.
@article{osti_1348023,
title = {A reduced resistive wall mode kinetic stability model for disruption forecasting},
author = {Berkery, J. W. and Sabbagh, S. A. and Bell, R. E. and Gerhardt, S. P. and LeBlanc, B. P.},
abstractNote = {},
doi = {10.1063/1.4977464},
journal = {Physics of Plasmas},
number = 5,
volume = 24,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2017},
month = {Mon May 01 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1063/1.4977464

Citation Metrics:
Cited by: 3works
Citation information provided by
Web of Science

Save / Share:
  • Two approaches for studying the damping of resistive wall modes due to wave particle resonant interactions are discussed. One approach uses the eigenfunction from an ideal MHD code combined with the resonant particle damping calculated from a drift-kinetic {delta}f- method formulation. This perturbative approach treats the wave-particle interaction precisely, but does not include the back-effect of the kinetic terms on the eigenfunction structure. In the alternate non-perturbative approach the kinetic terms are included in an MHD description via the pressure tensor. This non-perturbative approach includes the resonances due to the bounce and precessional drifts subject to certain approximations. Comparisons betweenmore » the two approaches and conclusions on the dominant stabilizing mechanisms are presented.« less
  • The resistive wall mode (RWM) instability in high-beta tokamaks is stabilized by energy dissipation mechanisms that depend on plasma rotation and kinetic effects. Kinetic modification of ideal stability calculated with the 'MISK' code [B. Hu et al., Phys. Plasmas 12, 057301 (2005)] is outlined. For an advanced scenario ITER [R. Aymar et al., Nucl. Fusion 41, 1301 (2001)] plasma, the present calculation finds that alpha particles are required for RWM stability at presently expected levels of plasma rotation. Kinetic stabilization theory is tested in an experiment in the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40,more » 557 (2000)] that produced marginally stable plasmas with various energetic particle contents. Plasmas with the highest and lowest energetic particle content agree with calculations predicting that increased energetic particle pressure is stabilizing but does not alter the nonmonotonic dependence of stability on plasma rotation due to thermal particle resonances. Presently, the full MISK model, including thermal particles and an isotropic slowing-down distribution function for energetic particles, overpredicts stability in NSTX experiments. Minor alteration of either effect in the theory may yield agreement; several possibilities are discussed.« less
  • The impact of collisionless, energy-independent, and energy-dependent collisionality models on the kinetic stability of the resistive wall mode is examined for high pressure plasmas in the National Spherical Torus Experiment. Future devices will have decreased collisionality, which previous stability models predict to be universally destabilizing. In contrast, in kinetic theory reduced ion-ion collisions are shown to lead to a significant stability increase when the plasma rotation frequency is in a stabilizing resonance with the ion precession drift frequency. When the plasma is in a reduced stability state with rotation in between resonances, collisionality will have little effect on stability.
  • The physics of kinetic effects on the resistive wall mode (RWM) stability is studied, and a comparison between reversed field pinch (RFP) and Tokamak configurations is made. The toroidal, magnetohydrodynamic (MHD)-kinetic hybrid stability code MARS-K, in which the drift kinetic effects are self-consistently incorporated into the MHD formulation, is upgraded with an extensive energy analysis module. In the tokamak configuration, the kinetic effect can stabilize the mode with very slow, or vanishing plasma rotation, due to the mode resonance with the toroidal precession drift of thermal trapped particles. In RFP, instead, stabilization of the RWM comes mainly from the ionmore » acoustic Landau damping (i.e., the transit resonance of passing particles). In the high beta region, the critical flow rotation frequency required for the mode stabilization is predicted to be in the ion acoustic range. Detailed physical analyses, based on the perturbed potential energy components, have been performed to gain understanding of the stabilizing mechanism in the two different systems.« less
  • Validating the calculations of kinetic resistive wall mode (RWM) stability is important for confidently predicting RWM stable operating regions in ITER and other high performance tokamaks for disruption avoidance. Benchmarking the calculations of the Magnetohydrodynamic Resistive Spectrum—Kinetic (MARS-K) [Y. Liu et al., Phys. Plasmas 15, 112503 (2008)], Modification to Ideal Stability by Kinetic effects (MISK) [B. Hu et al., Phys. Plasmas 12, 057301 (2005)], and Perturbed Equilibrium Nonambipolar Transport (PENT) [N. Logan et al., Phys. Plasmas 20, 122507 (2013)] codes for two Solov'ev analytical equilibria and a projected ITER equilibrium has demonstrated good agreement between the codes. The important particlemore » frequencies, the frequency resonance energy integral in which they are used, the marginally stable eigenfunctions, perturbed Lagrangians, and fluid growth rates are all generally consistent between the codes. The most important kinetic effect at low rotation is the resonance between the mode rotation and the trapped thermal particle's precession drift, and MARS-K, MISK, and PENT show good agreement in this term. The different ways the rational surface contribution was treated historically in the codes is identified as a source of disagreement in the bounce and transit resonance terms at higher plasma rotation. Calculations from all of the codes support the present understanding that RWM stability can be increased by kinetic effects at low rotation through precession drift resonance and at high rotation by bounce and transit resonances, while intermediate rotation can remain susceptible to instability. The applicability of benchmarked kinetic stability calculations to experimental results is demonstrated by the prediction of MISK calculations of near marginal growth rates for experimental marginal stability points from the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 (2000)].« less