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Fasoli, A.*; Gormezano, C.*; Berk, H. L.*; Breizman, B.*; Briguglio, S.*; Darrow, D. S.*; Gorelenkov, N.*; Heidbrink, W. W.*; Jaun, A.*; Konovalov, S. V.*; et al.
Nuclear Fusion, 47(6), p.S264 - S284, 2007/06
被引用回数：456 パーセンタイル：85.96(Physics, Fluids & Plasmas)ITERや将来の核融合炉では高速イオンのアルファ粒子がプラズマの維持に重要な役割を果たし、高速イオンが関連した物理現象の理解は重要である。本論文では、1999年の最初の「ITER物理基盤の進展」に関するレポート以降の高速イオンが絡む高温プラズマの物理現象についての理解の進展についてまとめた。高速イオンの物理機構を理解するための高速イオン源の進展,トロイダル磁場リップルによる高速イオン閉じ込めの理解の進展,高速イオンと背景プラズマ起因MHDの相互作用の理解の進展,高速イオン起因MHDの線形安定性の理解の進展,高速イオンと高速イオン起因MHDの相互作用と非線形発展の理解の進展,高速イオン起因MHDによる高速イオンの輸送の理解の進展について、実験計測,理論,数値計算で得られた成果をまとめている。
n modes in JT-60UBriguglio, S.*; Fogaccia, G.*; Vlad, G.*; Zonca, F.*; 篠原 孝司; 石川 正男; 武智 学
Physics of Plasmas, 14(5), p.055904_1 - 055904_10, 2007/05
被引用回数：42 パーセンタイル：79.54(Physics, Fluids & Plasmas)The results of particle-in-cell simulations of a negative neutral beam heated Alfvn-mode experiment in the JT-60U are presented. They seem to match quite well the dynamics of the abrupt large-amplitude event (ALE) experimentally observed in the reference JT-60U discharge. The time scale and frequency spread of the ALE are well reproduced too. The issue of the weaker Alfvn fluctuation phase following the ALEs, characterized by fast frequency sweeping modes, is also investigated and an interpretation of the full JT-60U bursting-mode phenomenology is presented. Finally, the simulation tool is exploited by ad hoc synthetic diagnostics on the fast ion distribution function to get a deeper insight into the ALE nonlinear dynamics. The underlying fast-growing energetic particle mode saturates as resonant energetic ions are scattered out of the resonance region and displaced outwards. The radially displaced ions resonate with outer Alfvn modes and enhance their local drive.
n-mode dynamics in JT-60U dischargesVlad, G.*; Briguglio, S.*; Fogaccia, G.*; 篠原 孝司; 石川 正男; 武智 学; Zonca, F.*
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03
JT-60Uの負イオン源中性粒子ビームを用いたアルベン固有モード実験に対するHMGC particle-in-cellコードを用いた粒子数値計算である。ALEと呼ばれている不安定性について、線形成長過程では、高エネルギーイオン圧力勾配の強いところにたつアルベン連続スペクトルと強く相互作用した高エネルギー粒子駆動不安定性であることがわかった。非線形過程では高エネルギーイオンの輸送が観測され、時間スケールも含め、実験データを再現している。
Bierwage, A.; Di Troia, C.*; Zonca, F.*
no journal, ,
A new software tool is presented which allows to initialize particle simulations of magnetically confined plasmas with an arbitrary particle distribution function. Besides facilitating simulations with (in principle) arbitrary spatial localization and velocity-space anisotropicity, the distinguishing feature of this tool is that it allows to construct an exact kinetic equilibrium for cases where magnetic drift orbits play an important role. One timely example is the interaction between energetic ions and magnetohydrodynamic modes in tokamaks used to study burning plasma conditions. In such cases, input data that consists of measurable (and physically meaningful) quantities is not sufficient to uniquely describe the equilibrium distribution function. The additional information required to design an exact equilibrium from incomplete input data is obtained by pre-computing the unperturbed drift orbits of all phase-space samples. Marker particles are distributed along these trajectories (excluding loss orbits) and appropriate weight factors are assigned. First simulation results with the new marker loading module will be presented as they become available.
