中文摘要：

高约束模式（H模）下自发产生的边缘局域模（ELM），虽然利于控制等离子体密度和排出杂质粒子从而实现H模放电的稳态运行，但是ELM爆发携带的大量粒子和能量会对装置的第一壁材料造成很大的损坏，所以在下一代聚变装置上使用之前很多装置已经开始了对ELM的研究．在HL．2A装置上观察到了不同的ELM，扰动幅度小的ELM引起的等离子体储能损失小于3％，ELM之间的时间间隔约为3ms，表现出Ⅲ型ELM的特征；扰动幅度较大的ELM的爆发对等离子体电流、等离子体密度及储能都有很明显的扰动，对等离子体储能的扰动大于10％，ELM爆发的频率随通过等离子体磁分界面的净加热功率的增加而增加，表现出明显的I型ELM的特征．ELM先兆有不对称性，在弱场侧磁探针信号能观测到，但强场侧却观测不到；ELM先兆的频率约为45kHz，观测到的最长的先兆先于ELM前约10ms出现．

英文摘要：

The edge-localized modes （ELMs） are often excited in an H-mode plasma, and they are helpful for cleaning the H-mode plasma to sustain a steady state for a longer time by controlling plasma density and exhausting impurities, but energy and particles carded by ELM burst will badly damage the first-wall of fusion device, thus the characteristics of and the control and mitigation of ELM are studied necessarily prior to the basic operational regime operating on ITER. ELMs of different perturbation amplitudes are observed experimentally on HL-2A tokamak. The frequency of small perturbation amplitude ELM decreases with the increase of net heating power, and it is about 300--400 Hz, and energy loss induced by per ELM is usually less than 3% of the plasma energy. The small ELM is type III ELM. While for large （type-I） ELM, besides that the energy loss induced by an ELM is generally more than 10%, they also exert an obvious perturbation on other plasma parameters, such as plasma current and electron density, and the tELM may be longer than 30 ms. ELM precursors are poloidally asymmetric, which can be measured by Mirnov probes on the low field side, but not on the high field side; the frequency of ELM precursors is about 45 kHz, and the longest precursors last approximately 10 ms prior to the ELM bursts.