帕克太阳探测器对湍流相干结构附近质子相对于α粒子优先加热的观测
Parker Solar Probe Observations of Preferential Heating of Protons over Alpha Particles near Turbulent Coherent Structures
AI总结：
基于帕克太阳探测器观测，用PVI方法发现太阳风湍流相干结构内质子比α粒子优先加热，呈各向异性，温度特征与流速及碰撞年龄变化吻合，为太阳风能量转换和离子热力学提供新认识。
AI中文摘要：
太阳风α粒子相对于质子呈现出优先加热和加速；然而，它们在湍流相干结构附近的行为仍了解较少。我们基于帕克太阳探测器（PSP）的观测，报告了使用增量部分方差（PVI）方法识别出的相干结构内局部α粒子和质子加热的首个证据。结果表明，高PVI事件与显著的、与物种相关的温度增强有关：质子的温度升高相对大于α粒子。这种质子优先加热导致α与质子温度比局部降低，表明等离子体被驱动向物种间的热平衡。加热也是各向异性的，以垂直温度增强为主。这些温度特征与归一化α-质子微分流速的显著降低和库仑碰撞年龄的局部最小值相吻合，表明弛豫主要受无碰撞动力学效应影响。这些发现为太阳风中的间歇性能量转换和离子热力学提供了新见解。
英文摘要：
Solar wind alpha particles exhibit preferential heating and acceleration relative to protons; however, their behavior in the vicinity of turbulent coherent structures remains less understood. We report the first evidence of localized alpha particle and proton heating within coherent structures identified using the Partial Variance of Increments (PVI) method, based on Parker Solar Probe (PSP) observations. Our results show that high-PVI events are associated with significant, species-dependent temperature enhancements: protons undergo a relative larger temperature increase than alpha particles. This preferential proton heating produces a localized decrease in the alpha-to-proton temperature ratio, indicating that the plasma is driven toward thermal equilibration between species. The heating is also anisotropic, being dominated by enhancements in the perpendicular temperature. These temperature-signatures coincide with a pronounced reduction in the normalized alpha-proton differential flow speed and a localized minimum in the Coulomb collision age, suggesting that the relaxation is affected primarily by collisionless kinetic effects. These findings provide new insight into the intermittent energy conversion and ion thermodynamics in the solar wind.
