Implications of Near Solar Source Pickup Ions

研究人员将研究太阳风中主要的日球层拾取离子源，它们的传播和加速。拾取离子是由中性原子在等离子体磁场中电离并开始旋转时产生的。在太阳风的情况下，从缓慢移动的中性粒子产生的拾取离子的初始速度几乎等于太阳风的速度，因为它们随着太阳风的磁场被输送出去。因此，拾取过程产生了更高能量，因此更容易观察到的离子群，可以用来推断产生它们的中性环境的性质。在日光层中，有三种主要的拾取离子：来自星际中性的星际拾取离子，由行星际尘埃和太阳风相互作用产生的内源拾取离子，以及来自彗星、行星和其他离散来源的离散源拾取离子。研究人员将通过模拟近太阳和星际来源产生的拾取离子的分布函数和流体动力学性质来表征近太阳拾取离子源的特征。他们还将研究近太阳来源的拾取离子、星际来源的拾取离子和太阳风粒子作为高能粒子和反常宇宙射线的种子种群的相对重要性。

The investigators will study major heliospheric pickup ion sources in the solar wind, their propagation and acceleration. Pickup ions are generated from neutral atoms when they become ionized and begin to gyrate in a plasma's magnetic field. In the case of the solar wind, pickup ions born from slowly moving neutrals acquire an initial speed nearly equal to the solar wind speed as they are transported out with the solar wind's magnetic field. The pickup process thereby creates a more energetic and therefore more easily observed population of ions that may be used to infer properties of the neutral environment from which they were created. In the heliosphere, there are three main populations of pickup ions: interstellar pickup ions from interstellar neutrals, inner source pickup ions created by interactions between interplanetary dust and the solar wind, and discrete source pickup ions from comets, planets, and other discrete sources. The investigators will characterize near-solar pickup ion sources by modeling distribution functions and hydrodynamic properties of pickup ions produced from near-solar and interstellar sources. They will also study the relative significance of near-solar source pickup ions, interstellar source pickup ions, and solar wind particles as seed populations for energetic particles and anomalous cosmic rays.