Impact of particle sources and plasma resistivity on edge localized modes

The impact of particle sources and resistivity on edge localized mode (ELM) mitigation dynamics has been studied using the BOUT++ code for particle sources deposited at different locations of the pedestal. For the particle source deposited at the pedestal middle, in the linear and initial crash phases the amplitude of the particle source plays a key role in reducing the ELM size, whereas in the relaxation phase the width of the particle source becomes important in limiting the ELM size. For the case of the particle source deposited at the pedestal bottom, the impact of particle sources on the ELM size in the initial crash phase is generally weak and the width of the particle source appears more efficient in decreasing the ELM size than the source amplitude. However, in the relaxation phase the amplitude of the particle source can significantly modify the local density and temperature, resulting in a reduced parallel viscocity and generation of zonal flows, and consequently, reduction of the ELM size. The simulation indicates that in the above two cases a small plasma resistivity does not affect the ELM mitigation process.