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Nonlinear {omega}*-stabilization of the m = 1 mode in tokamaks

Technical Report ·
DOI:https://doi.org/10.2172/100284· OSTI ID:100284
 [1];  [2]
  1. Univ. of Maryland, College Park, MD (United States). Inst. for Plasma Research
  2. Princeton Univ., NJ (United States). Plasma Physics Lab.
Earlier studies of sawtooth oscillations in Tokamak Fusion Test Reactor supershots (Levinton et al, Phys. Rev. Lett. 72, 2895 (1994); Zakharov, et al, Plasma Phys. and Contr. Nucl. Fus. Res., Proc. 15th Int. Conf., Seville 1994, Vienna) have found an apparent contradiction between conventional linear theory and experiment: even in sawtooth-free discharges, the theory typically predicts instability due to a nearly ideal m = 1 mode. Here, the nonlinear evolution of such mode is analyzed using numerical simulations of a two-fluid magnetohydrodynamic (MHD) model. We find the mode saturates nonlinearly at a small amplitude provided the ion and electron drift-frequencies {omega}*{sub i,e} are somewhat above the linear stability threshold of the collisionless m = 1 reconnecting mode. The comparison of the simulation results to m = 1 mode activity in TFTR suggests additional, stabilizing effects outside the present model are also important.
Research Organization:
Princeton Univ., NJ (United States). Plasma Physics Lab.
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
AC02-76CH03073
OSTI ID:
100284
Report Number(s):
PPPL--3125; ON: DE95017398
Country of Publication:
United States
Language:
English

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