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An eight-channel poloidal correlation reflectometer (PCR) with O-mode polarization has been installed in the EAST tokamak to measure the fluctuations from core to edge. The PCR launches eight different frequency microwaves (20.4, 24.8, 33, 40, 42.4, 48, 52.6, 57.2 GHz) into the plasma from the low field side and two poloidally separated antennae are used to receive the reflected waves. As a result, the diagnostic can measure fluctuations in eight (radial)× two (poloidal) spatial positions. The diagnostic has been applied to study the core and edge pedestal fluctuations during an inter-ELM phase in H-mode plasma. This inter-ELM phase can be divided into two stages. In the first stage, a low frequency (

A cross-scale interaction between a kink instability with toroidal mode number (n) of 1 and background microturbulence (mainly a coherent mode with n = 12–17) has been observed in the H-mode edge pedestal region in the EAST tokamak. The n = 1 kink mode with a frequency ~3.5 kHz is localized in the pedestal region. The amplitude of pedestal microturbulence is evidently modulated at the frequency of the n = 1 mode. This amplitude modulation is mainly for the fluctuation component with frequency less than 100 kHz, while no modulation by the n = 1 mode is observed for the component with frequency larger than 100 kHz. This implies that the observed amplitude modulation by the n = 1 mode is not due to the Doppler shift effect. A further analysis shows that the amplitude modulation of microturbulence could be attributed to modulation of the local temperature gradient by the n = 1 kink mode. In addition, bicoherence analysis indicates that there exists a possible direct nonlinear interaction between background microturbulence and the n = 1 kink instability. A preliminary analysis shows that this cross-scale interaction has no evident effect on the pedestal structure.