Non-local transport phenomenon with SMBI on HL-2A

The non-local transport phenomena induced by supersonic molecular beam injection (SMBI) has been firstly observed in HL-2A tokomak in both the low density discharges and the high density discharges. For low density (less than 1.5 x 10¹⁹ m^-3, besides the similarities with the phenomena induced by other methods in various Tokamaks, the results on HL-2A show some experimental progress in this effect: the duration of the effect induced by SMBI in HL-2A could be prolonged by changing the condition of SMBs injection; both the bolometer radiation and the H_a emission decrease when the non-local effect appears in low density. Repetitive non-local effect induced by modulated SMBs allows Fourier transformation of the temperature perturbation, yielding detailed investigation of the pulse propagation. The investigation indicates that, although the fast core T_e response to edge cooling in high density is opposite to that in low density, the nonlocality of electron heat transport appears in both the two conditions. Analytic results also suggest a common underlying physical mechanism between the 'non-local' transport phenomena in the two different conditions. (author)