摘要： Excitation of geodesic acoustic mode (GAM) by collisionless trapped electron mode (CTEM) is studied within the framework of nonlinear gyrokinetic theory. The dispersion relation describing GAM excitation by drift wave turbulence valid for arbitrary k⊥ρi is derived. Here, k⊥ and ρi are, respectively, perpendicular wave vector and thermal ion Larmor radius. It is found that the parametric decay process of CTEM into a GAM and a CTEM sideband is unstable in both small and large k⊥ρi regimes due to, respectively, ion and trapped electron nonlinearity. For moderate k⊥ρi, however, there exists a negligible-GAM-excitation state where ion and trapped electron nonlinearities cancel each other. 其他題名： NF 其他題名： Nucl. Fusion 出版者： IOP Publishing 出版日期： 2014-03-01 出處： Nuclear Fusion, 2014-03, Vol.54 (3), p.33010-6 資源來源： IoP Science journals 版權： 2014 IAEA, Vienna 識別號： ISSN: 0029-5515 識別號： EISSN: 1741-4326 識別號： DOI: 10.1088/0029-5515/54/3/033010 識別號： CODEN: NUFUAU
