Verification of Energetic-Particle-Induced Geodesic Acoustic Mode in Gyrokinetic Particle Simulations

• 作者: Chao Dong Ding Li Jian Bao Jintao Cao Wenlu Zhang Yang Chen Zhihong Lin
• 来源期刊: 中国物理快报（英文版）
• 年，卷（期）: 2020,（9）
• 所属期刊栏目: PHYSICS OF GASES,PLASMAS,AND ELECTRIC DISCHARGES
• 页码范围: 36-41
• 页数: 6页
• 语种: 英文
• DOI: 10.1088/0256-307X/37/9/095201

摘要

The energetic-particle-induced geodesic acoustic mode (EGAM) is studied using gyrokinetic particle simulations in tokamak plasmas.In our simulations,exponentially growing EGAMs are excited by energetic particles with a slowing-down distribution.The frequencies of EGAMs are always below the frequencies of GAMs,which is due to the non-perturbative contribution of energetic particles (EPs).The mode structures of EGAMs are similar to the corresponding mode structures of GAMs.Our gyrokinetic simulations show that a high EP density can enhance the EGAM growth rate,due to high EP free energy,and that EPs' temperature and the pitch angle of the distribution modify the EGAM frequency/growth rate by means of the resonance condition.Kinetic effects of the thermal electrons barely change the EGAM frequency,and have a weak damping effect on the EGAM.Benchmarks between the gyrokinetic particle simulations and a local EGAM dispersion relation exhibit good agreement in terms of EGAM frequency and growth rate.