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The rapid inward diffusion of cold ions in tokamaks and their effect on ion transport

Technical Report ·
DOI:https://doi.org/10.2172/5072560· OSTI ID:5072560
The observed increase with density of the density asymmetry caused by the centrifugal force of toroidal motion in PDX, which is contrary to conventional theory, is explained by the presence of an excess of low energy ions with 10--15% concentration. The prime source being recycling, it is shown that low energy ions undergo rapid inward diffusion (too rapid to thermalize with the outward diffusion energetic ions) due to the combined effects of large {nu}{sub PA}, electrostatic diffusion, and negative E{sub r} and {partial derivative}T{sub i}/{partial derivative}r. The presence of the low energy ions alters dramatically the predictions of neoclassical theory and many hydrogen and impurity ion transport phenomena now have simple explanations. 19 refs., 2 figs.
Research Organization:
Texas Univ., Austin, TX (USA). Inst. for Fusion Studies
Sponsoring Organization:
DOE/ER
DOE Contract Number:
FG05-80ET53088
OSTI ID:
5072560
Report Number(s):
DOE/ET/53088-405; IFSR--405; ON: DE90006863
Country of Publication:
United States
Language:
English