SHINE: Statistical Analysis of Magnetic Helicity of the Solar Wind Turbulence at Kinetic Scales

该项目的研究议程直接涉及SHINE的目标，即“理解或描述背景太阳风及其演变方式”。“研究工作的成果将促进对动力学尺度行星际湍流的理解。 预计该项目将为空间物理学提供基本的新见解，了解大规模磁流体动力学湍流的无碰撞耗散实际上如何在太阳风中进行。 整体努力包括来自新罕布什尔州大学的学生的参与。 该项目的研究和EPO议程支持AGS部门在发现，学习，多样性和跨学科研究方面的战略目标。这个为期3年的SHINE项目的主要目标是研究质子动力学范围内与行星际湍流波动相关的磁螺旋度。 磁螺旋度是湍流能量级联物理过程的敏感指标。 项目小组将使用来自Wind的航天器数据来确定磁螺旋度的统计特性。 螺旋度的分布与对流通过航天器的规模将被描述的值和位置达到峰值，也是它的宽度在半最大值。 这些属性将被研究的波动，等离子体β，和交叉螺旋的振幅的函数。 磁螺旋度的光谱特性将使用来自相同数据集的全球和局部平均磁场进行计算。 这将允许这两种技术所获得的统计结果之间的直接比较。 粒子离子和流体电子的三维混合数值模拟也将被用来解释在每种方法中发现的结果。

The research agenda of this project directly addresses the SHINE goal of "understanding or characterizing the background solar wind and how it evolves." The outcome of the research work will advance the understanding of interplanetary turbulence at the kinetic scales. This project is expected to provide fundamental new insights in space physics regarding how collisionless dissipation of large-scale magnetohydrodynamic turbulence actually proceeds in the solar wind. The overall effort includes the participation of students from the University of New Hampshire. The research and EPO agenda of this SHINE project supports the Strategic Goals of the AGS Division in discovery, learning, diversity, and interdisciplinary research. The main goal of this 3-year SHINE project is to study the magnetic helicity associated with interplanetary turbulent fluctuations in the proton kinetic range. The magnetic helicity is a sensitive indicator of the physical processes responsible for the turbulent energy cascade. The project team will use spacecraft data from Wind to determine the statistical properties of the magnetic helicity. The distribution of the helicity with the scale convected past the spacecraft will be described by the value and position attained at the peak and also its width at half maximum. These properties will be studied as functions of the amplitude of the fluctuations, the plasma beta, and the cross-helicity. The spectral properties of the magnetic helicity will be calculated using both global and local mean magnetic fields from the same data sets. This will allow a direct comparison between the obtained statistical results of these two techniques. Three-dimensional hybrid numerical simulations with particle ions and fluid electrons will also be used to interpret the results found in each approach.