ELM divertor heat flux with edge harmonics oscillation in NSTX

Previously, strike point splitting induced by an edge harmonic oscillation (EHO) was observed in NSTX (K.F. Gan et al., 2017 Nucl. Fusion 57 126053). The EHO also appears during inter-ELM. The rotation of the EHO was accelerated when the ELM appeared, and the EHO disappeared quickly during the ELM decay time. During the ELM rise time, the ELM divertor heat flux distribution is consistent to the divertor heat flux with EHO, which indicates that the ELM heat flux deposited on the divertor has an n=1 strike point splitting structure. During the ELM decay, the disappearance of the EHO caused the strike point splitting to disappear along with a narrowing of the heat flux distribution. The integral heat flux (λ_int) within the ELM decay time is decreased by 50% compared to that at the ELM peak time; while the deposited power during the ELM decay time decreased slowly, such that the peak heat flux at the ELM decay time could be >100% larger than the peak heat flux at the ELM peak time.