ISSN:
1089-7674
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The nonlinear evolution of radiative modes with the effects of finite recombination time were studied in a uniformly magnetized quasi two-dimensional plasma. In the one-dimensional limit, it was found that a plasma in noncoronal equilibrium (impurities evolve at a slower rate than the temperature), radiative modes were modestly more stable and evolved at a slower rate. A new unstable state was found in which the plasma initially cooled, only to grow unstable to the radiative condensation mode. This nonlinearly unstable regime has a stability boundary an order of magnitude higher than that predicted by linear theory. For a parameter regime appropriate to the tokamak edge, the nonlinear condensation mode proved to be more unstable in noncoronal equilibrium than in coronal equilibrium. When two-dimensional effects were added, little difference was found in the behavior of the mode in coronal equilibrium, but in noncoronal equilibrium, a new state evolved in which the condensation initially grew, but then flattened as the plasma continued to heat at a constant rate. The results provide insight as to why condensations are observed in tokamaks when they are seemingly stable to condensation modes. © 1997 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.872235
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