Comparison of Spatiotemporal Turbulence Characteristics in HL-2A and DIII-D Plasmas*

The 2D spatiotemporal characteristics of long-wavelength density fluctuations arising from turbulence are measured and compared on the HL-2A and DIII-D tokamaks with beam emission spectroscopy (BES) to better understand the influence of tokamak geometry, magnetic configuration, local and global plasma parameters, and heating methods on turbulence characteristics and the resulting transport properties. The toroidal magnetic fields and major radii are comparable on HL-2A and DIII-D, while HL-2A has a smaller minor radius and typically one-third the plasma current of DIII-D. Turbulence characteristics are compared with dominant ion and electron heating with NBI, ECH, and LHCD (on HL-2A). The impact of varying ion gyroradius, T_e/T_i ratio, and q₉₅ on radial and poloidal correlation lengths, decorrelation times, and fluctuation amplitude profiles and resulting transport behavior will be examined and compared. Analysis of angular momentum transport will be emphasized with an aim to understanding the role of turbulence in intrinsic torque drive and cross-field transport.