@article{oai:repo.qst.go.jp:00047803,
 author = {ビアワーゲ, アンドレアス and 篠原, 孝司 and ビアワーゲ アンドレアス and 篠原 孝司},
 issue = {4},
 journal = {Physics of Plasmas},
 month = {Apr},
 note = {The nonlinear interactions between shear Alfven modes and tangentially injected beam ions in the 150–400 keV range are studied numerically in a JT-60U tokamak scenario with realistic geometry, large magnetic drifts, and strong beam drive. For this purpose, the recently developed orbit-based resonance analysis (ORA) method for circulating particles is extended, so that it can be applied to the nonlinear regime, where the spectrum of orbit-based poloidal mode numbers m orb varies in time as the fast ions undergo wave-particle trapping and radial transport. In particular, the extended ORA method captures the effect of nonlinear overlaps between resonances associated with neighboring harmonics (m_orb, n) and (m_orb+1, n) that cause long-distance ballistic transport. Two cases with low toroidal mode numbers n >= 1 are studied: an n = 1 mode without resonance overlap and a strongly driven n = 3 mode with resonance overlap. For both cases, an effective radial profile of the resonant poloidal mode number m_res = M_eff(r) is computed and used to track the effective resonant frequency w_res(t) of individual particles during their radial motion r(t). In Paper II, this frequency tracking technique will be applied to study the nonlinear frequency chirping and convective amplification of the modes.},
 pages = {042511-1--042511-20},
 title = {Orbit-based analysis of nonlinear energetic ion dynamics in tokamaks. I. Effective mode number profile and resonant frequency tracking},
 volume = {23},
 year = {2016}
}