Long radial coherence of electron temperature fluctuations in non-local transport in HL-2A plasmas

The dynamics of long-wavelength (k(theta) < 1.4 cm(-1)), broadband (20 kHz-200 kHz) electron temperature fluctuations (T-e(similar to)/T-e) of plasmas in gas-puff experiments are observed for the first time in HL-2A tokamak. In a relatively low density (n(e)(0) similar or equal to 0.91 x 10(19)m(-3)-1.20 x 10(19)m(-3)) scenario, after gas-puffing the core temperature increases and the edge temperature drops. On the contrary, temperature fluctuation drops at the core and increases at the edge. Analyses show the non-local emergence is accompanied with a long radial coherent length of turbulent fluctuations. While in a higher density (n(e)(0) similar or equal to 1.83 x 10(19) m(-3)-2.02 x 10(19) m(-3)) scenario, the phenomena are not observed. Furthermore, compelling evidence indicates that E x B shear serves as a substantial contributor to this extensive radial interaction. This finding offers a direct explanatory link to the intriguing core-heating phenomenon witnessed within the realm of non-local transport.