[P-EM17] 宇宙プラズマ理論・シミュレーション

[PEM17-P05] Parametric study of the harmonic structure of lower hybrid waves driven by energetic ions

*小谷 翼¹、樋田 美栄子²、森高 外征雄²、田口 聡¹ (1.京都大学、2.核融合科学研究所)

キーワード：低域混成波の高調波、リング分布を持つ高速イオン、電磁粒子シミュレーション

Using one-dimensional, electromagnetic, particle-in-cell simulations, we report the excitation and non-linear development of the harmonic structure of lower hybrid waves driven by ring-like energetic ions under a wide range of parameters (ω_pe/Ω_e, u_⊥/v_A, and m_i/m_e, etc.). Here, ω_pe/Ω_e is the ratio of the electron plasma frequency to the electron cyclotron frequency, u_⊥/v_A is the ratio of the ring velocity of energetic ions to the Alfvén velocity, and m_i/m_e is the ion-to-electron mass ratio. Our previous studies have found that energetic ions can excite harmonic lower hybrid waves under the conditions of m_i/m_e = 1000, ω_pe/Ω_e = 0.25, and u_⊥/v_A, = 0.6 [1] and m_i/m_e = 1836, ω_pe/Ω_e = 0.1 or 0.2, and u_⊥/v_A = 0.011 or 0.022 [2]. However, their generation condition remains unclear. Focusing particularly on the two parameters of ω_pe/Ω_e and u_⊥/v_A, we investigate the favorable condition for the generation of harmonic lower hybrid waves.

References
[1] T. Kotani, M. Toida, T. Moritaka, and S. Taguchi, Simulation study of the harmonic structure of lower hybrid wave driven by energetic ions, Physical Review E, in revision.
[2] T. Kotani, M. Toida, T. Moritaka, and S. Taguchi, Harmonic Structure of Lower Hybrid Waves Driven by Energetic Ions at 4000 km Altitude: PIC Simulation, Geophysical Research Letters, in revision.