Teaca Bogdan, Weidl Martin S, Jenko Frank, Schlickeiser Reinhard
Applied Mathematics Research Centre, Coventry University, Coventry CV1 5FB, United Kingdom and Max-Planck/Princeton Center for Plasma Physics and Max-Planck-Institut für Plasmaphysik, D-85748 Garching, Germany and Max Planck Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077, Göttingen, Germany.
Max-Planck/Princeton Center for Plasma Physics and Max-Planck-Institut für Plasmaphysik, D-85748 Garching, Germany.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Aug;90(2):021101. doi: 10.1103/PhysRevE.90.021101. Epub 2014 Aug 11.
The present work investigates the acceleration of test particles, relevant to the solar-wind problem, in balanced and imbalanced magnetohydrodynamic turbulence (terms referring here to turbulent states possessing zero and nonzero cross helicity, respectively). These turbulent states, obtained numerically by prescribing the injection rates for the ideal invariants, are evolved dynamically with the particles. While the energy spectrum for balanced and imbalanced states is known, the impact made on particle heating is a matter of debate, with different considerations giving different results. By performing direct numerical simulations, resonant and nonresonant particle accelerations are automatically considered and the correct turbulent phases are taken into account. For imbalanced turbulence, it is found that the acceleration rate of charged particles is reduced and the heating rate diminished. This behavior is independent of the particle gyroradius, although particles that have a stronger adiabatic motion (smaller gyroradius) tend to experience a larger heating.
本研究探讨了与太阳风问题相关的测试粒子在平衡和不平衡磁流体动力学湍流（此处术语分别指具有零和非零交叉螺旋度的湍流状态）中的加速情况。这些湍流状态通过规定理想不变量的注入率进行数值获取，并与粒子一起动态演化。虽然平衡和不平衡状态的能谱是已知的，但对粒子加热的影响存在争议，不同的考虑因素给出了不同的结果。通过进行直接数值模拟，自动考虑了共振和非共振粒子加速，并考虑了正确的湍流相位。对于不平衡湍流，发现带电粒子的加速率降低，加热率减小。这种行为与粒子回旋半径无关，尽管具有较强绝热运动（较小回旋半径）的粒子往往经历更大的加热。
