Isotope scaling and {eta}{sub i} mode with impurities in tokamak plasmas

Technical Report · Fri Apr 01 04:00:00 EST 1994

DOI:https://doi.org/10.2172/10154987· OSTI ID:10154987

Dong, J Q; Horton, W; Dorland, W D

The ion temperature gradient driven instability, or {eta}{sub i} mode, is studied for discharges with hydrogen, deuterium or tritium in a toroidal magnetic configuration. Impurity effects on the mode and the instability which is driven by the presence of impurity ions (impurity modes) are studied as well. It is found that the maximum growth rate of the {eta}{sub i} mode scales as M{sup {minus}{1/2}} for pure hydrogen, deuterium or tritium discharges, where M is the mass of the working gas ion. With the inclusion of impurity ions the growth rates of {eta}{sub i} mode decrease in all three kinds of plasmas with a hydrogen plasma still having the highest maximum growth rate, tritium the lowest, and deuterium in between. However, the isotope effects are weaker and scale as M{sub eff}{sup {minus}{1/2}} with the presence of impurity ions, where the effective mass M{sub eff} is a combination of A{sub i} and A{sub z}, the mass number of hydrogenic and impurity ions. For the impurity mode the situation is similar to that of the {eta}{sub i} mode without impurity ions. Experimental database shows that the plasma energy confinement time scales as {tau}{sub E}{approximately}A{sub i}{sup {1/2}} in clean plasmas. The correlation of the theoretical results with the experimental confinement scaling is discussed.

• Research Organization: Texas Univ., Austin, TX (United States). Inst. for Fusion Studies
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG05-80ET53088
• OSTI ID: 10154987
• Report Number(s): DOE/ET/53088--654; IFSR--654; ON: DE94012763; BR: 39KG01000/AT0520240
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700310
700340
CONFINEMENT TIME
DRIFT INSTABILITY
INSTABILITY GROWTH RATES
ION TEMPERATURE
PLASMA CONFINEMENT
PLASMA IMPURITIES
PLASMA MICROINSTABILITIES
PLASMA WAVES, OSCILLATIONS, AND INSTABILITIES
SCALING LAWS
TEMPERATURE GRADIENTS
THEORETICAL DATA
TOKAMAK DEVICES