arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1406.0678astro-ph.SR
收藏

利用Turbulence和离子回旋共振模拟太阳风质子加热

Ensemble Simulations of Proton Heating in the Solar Wind via Turbulence and Ion Cyclotron Resonance

Steven R. Cranmer

摘要:

质子在日冕和日球层表现出各向异性的速度分布,违反磁矩守恒,并普遍缺乏与其他粒子的热平衡。关于在太阳风中激发非麦克斯韦质子的物理过程的身份还没有达成一致,但传统上最喜欢的是离子回旋共振阿尔芬波的耗散。本文提出了动力学模型,离子回旋波加热质子的旅程从日冕到行星际空间。它还得到了广泛的新的解决方案,相关的色散关系,边际稳定边界,和非共振速度空间扩散率。本文建立了一个包含回旋阻尼和湍流级联的唯象模型来解释低α-质子微分流速下质子加热的抑制。这些影响是在一个大规模的模型中实现的质子热演化从日冕1 AU。一个真实的风速,密度,磁场强度,和加热率的蒙特卡罗合奏产生一个充满的区域的参数空间(在一个平面所描述的平行等离子体β和质子温度各向异性比)类似的测量。该填充区域的高β边缘由等离子体不稳定性和强加热速率控制。低β边缘对应于较弱的质子加热和回旋共振的相对贡献范围。总的来说,这些模型与其他研究一致,这些研究发现只有一小部分湍流功率谱需要由离子回旋波组成。

英文摘要:

Protons in the solar corona and heliosphere exhibit anisotropic velocity distributions, violation of magnetic moment conservation, and a general lack of thermal equilibrium with the other particle species. There is no agreement about the identity of the physical processes that energize non-Maxwellian protons in the solar wind, but a traditional favorite has been the dissipation of ion cyclotron resonant Alfven waves. This paper presents kinetic models of how ion cyclotron waves heat protons on their journey from the corona to interplanetary space. It also derives a wide range of new solutions for the relevant dispersion relations, marginal stability boundaries, and nonresonant velocity-space diffusion rates. A phenomenological model containing both cyclotron damping and turbulent cascade is constructed to explain the suppression of proton heating at low alpha-proton differential flow speeds. These effects are implemented in a large-scale model of proton thermal evolution from the corona to 1 AU. A Monte Carlo ensemble of realistic wind speeds, densities, magnetic field strengths, and heating rates produces a filled region of parameter space (in a plane described by the parallel plasma beta and the proton temperature anisotropy ratio) similar to what is measured. The high-beta edges of this filled region are governed by plasma instabilities and strong heating rates. The low-beta edges correspond to weaker proton heating and a range of relative contributions from cyclotron resonance. On balance, the models are consistent with other studies that find only a small fraction of the turbulent power spectrum needs to consist of ion cyclotron waves.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑