Intermittent convective transport suppressed by supersonic molecular beam injection on the HL-2A tokamak

Abstract

Edge localized mode (ELM)-filament statistical characteristics and intermittent convective transport are studied during ELM mitigation (10–30 ms) induced by supersonic molecular beam injection (SMBI) on the HL-2A tokamak. Langmuir probe data show that the burst rate of large amplitude filaments (δne > 4σ) decreases by 30–50% and their radial velocity decreases by 40–60%, which is an indication of an amplitude reduction. A decrease of long-range correlation along the magnetic flux surface is observed after SMBI, indicating a role of electron–ion collisionality on the filament parallel current in the ELM mitigation time. The transient particle and heat fluxes decrease about 40–50% and 50–60%, respectively. These observations indicate that SMBI might be an effective method to suppress the intermittent convective transport.