A coherent mode (CM) in the edge pedestal region has been observed on different fluctuation quantities, including density fluctuation, electron temperature fluctuation and magnetic fluctuation in H mode plasma on the Experimental Advanced Superconducting Tokamak (EAST) tokamak. Measurements at different poloidal positions show that the local poloidal wavenumber is smallest at the outboard midplane and will increase with poloidal angle. This poloidal asymmetry is consistent with the flute-like assumption (i.e. k // ∼0) from which the toroidal mode number of the mode has been estimated as between 12 and 17. It was further found that the density fluctuation amplitude of the CM also demonstrated poloidal asymmetry. The appearance of a CM can clearly decrease or even stop the increase in the edge density, while the disappearance of a CM will lead to an increase in the pedestal density and density gradient. Statistical analysis showed there was a trend that as the CM mode amplitude increased, the rate of increase of the edge density decreased and the particle flux (Γ div ) onto the divertor plate increased. The CM sometimes showed burst behavior, and these bursts led bursts on Γ div with a time of about 230 μs, which is close to the time for particle flow from the outer midplane to the divertor targets along the scrape-off layer magnetic field line. This evidence showed that the CM had an effect on the outward transport of particles.

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We present the analysis of SN 2020wnt, an unusual hydrogen-poor super-luminous supernova (SLSN-I), at a redshift of 0.032. The light curves of SN 2020wnt are characterised by an early bump lasting ∼5 days, followed by a bright main peak. The SN reaches a peak absolute magnitude of M$_{r}^{max}=-20.52\pm 0.03$ mag at ∼77.5 days from explosion. This magnitude is at the lower end of the luminosity distribution of SLSNe-I, but the rise-time is one of the longest reported to date. Unlike other SLSNe-I, the spectra of SN 2020wnt do not show O ii, but strong lines of C ii and Si ii are detected. Spectroscopically, SN 2020wnt resembles the Type Ic SN 2007gr, but its evolution is significantly slower. Comparing the bolometric light curve to hydrodynamical models, we find that SN 2020wnt luminosity can be explained by radioactive powering. The progenitor of SN 2020wnt is likely a massive and extended star with a pre-SN mass of 80 M⊙ and a pre-SN radius of 15 R⊙ that experiences a very energetic explosion of 45 × 1051 erg, producing 4 M⊙ of 56Ni. In this framework, the first peak results from a post-shock cooling phase for an extended progenitor, and the luminous main peak is due to a large nickel production. These characteristics are compatible with the pair-instability SN scenario. We note, however, that a significant contribution of interaction with circumstellar material cannot be ruled out.