Description
Micro-tearing modes (MTMs), electromagnetic instabilities driven by electron temperature gradients, are key to anomalous electron heat transport in magnetic confinement fusion plasmas. This work reports the first experimental identification of MTMs in the pedestal of EAST superconducting tokamak during inter-ELM periods of Elmy H-mode discharges. MTMs were detected via Electron Cyclotron Emission Imaging (ECEI), Mirnov magnetic coils, Backward Doppler Reflectometer (DBS), and Langmuir probes. The mode shows a "fork-shaped" time-frequency spectrum (80–120 kHz), propagating in the electron diamagnetic direction at ~40 km/s poloidal phase velocity and ~0.15 cm⁻¹ poloidal wave number. ECEI’s 2D imaging reveals asymmetric poloidal amplitude distribution, a signature MTM trait. Notably, ECEI-measured electron temperature and DBS-measured radial electric field fluctuations are anti-phase, consistent with the radial pressure balance equation. Divertor Langmuir probe data confirm outward particle flux is independent of MTM occurrence, validating MTMs do not affect particle confinement. This study provides direct experimental evidence of pedestal MTMs in EAST, complementing gyrokinetic simulations. Observed mode characteristics advance understanding of turbulence-driven transport in tokamak edge plasmas, supporting high-confinement regime optimization for future fusion devices like ITER.