ISSN:
1089-7623
Quelle:
AIP Digital Archive
Thema:
Physik
,
Elektrotechnik, Elektronik, Nachrichtentechnik
Notizen:
A novel method is presented to analyze internal disruptions (sawteeth), observed with the five-camera soft-x-ray diagnostic at the Rijnhuizen Tokamak Project (RTP). Using four or five cameras, tomographic images with seven poloidal harmonics have been obtained throughout sawtooth crashes and precursor oscillations. The detection of cross-field transport and magnetic reconnection from the reconstructed tomographic images is complicated by the fact that (except during the final phase of the collapse) the time dependence is dominated by the m=1 ideal MHD displacement of the hot core in combination with plasma rotation. It is possible to define quantities, e.g., the plasma volume where the emissivity is within a certain range, whose change is only determined by cross-field transport or reconnection, and are not affected by displacement and rotation. The good spatial resolution of the 80-channel system enables us to compute these quantities with such an accuracy that their sensitivity to plasma rotation and MHD convection is small. Using this approach we find in the sawteeth studied so far that m=1 magnetic reconnection may take place, but affects less than half of the magnetic flux within the q=1 surface, thus ruling out complete reconnection as a mechanism for the final collapse of the hot core in these cases. © 1995 American Institute of Physics.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.1146344
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