Difference in electron thermal diffusivity and profile between interior and exterior of TFTR L-mode plasmas.

摘要

The local properties such as scale lengths of the electron density (L(sub n(sub e))), temperature (L(sub T(sub e))), and pressure (L(sub p(sub e))), and the electron thermal diffusivity (chi)(sub e)(r) (m(sup 2)/s) for r/a > 0.3 have been studied for TFTR L-mode discharges under the assumption of (chi)(sub e) = (chi)(sub i). The scale lengths and the electron thermal diffusivity in the interior 0.3 < r/a < 0.55 are significantly different from those on the exterior 0.55 < r/a < 0.8. following are some examples (temperatures in keV, other quantities in MKS units). In the interior (0.3 < r/a < 0.55), most of the scale lengths were constant or a weakly dependent on radius, and (chi)(sub e) can be expressed as (with correlation coefficient R = 0.61), (chi)(sub e)(r) = 1.44 (times) 10(sup 18)(r/a)(sup 1.0)T(sub e)(r)(sup 0.1)q(r)(sup 0.1)/n(sub e)(sup 0.9)(r). In the exterior region (0.55 < r/a < 0.8), the scale lengths decrease monotonically, and (chi)(sub e) can be described as (with R = 0.68), (chi)(sub e)(r) = 2.3 (times) 10(sup 3)(r/a)(sup 1.7)T(sub e)(r)(sup 0.7)q(r)(sup 0.8)/n(sub e)(sup 0.2)(r). It is interesting to note the negative n(sub e) dependence of (chi)(sub e) in the interior and the positive T(sub e) dependence of (chi)(sub e) in the exterior.