Studies of the Solar Wind Near the Sun

20Ro以内的太阳风等离子体将利用各种无线电传播技术进行研究。这将允许估计密度起伏的空间谱、平均流速、其随机分量和磁场的方向。这些测量将与光学数据进行比较，例如白光日冕仪、磁力仪和发射线观测。基本目标将是更多地了解日冕加热的机制和临界点附近的能量流动，并研究快速流等大尺度结构的日冕起源。在20RO内，早期的观测显示随机速度迅速增加，在10到300公里尺度上的密度起伏中的过剩能量，以及变得高度各向同性的密度起伏。这项研究将使用多天线强度闪烁来测量粒子通过音速点的加速度。空间各向异性作为空间尺度的函数将通过比较角散射(在VLA测量)和位相闪烁(用VLBA测量)来测量。将对强度闪烁进行分析以了解随机速度分量的来源。最后，与距离太阳更远的地表测量相比，20 Ro以内的观测结果可以更准确地进行比较，因为测绘距离很小，流-流相互作用也不那么重要。将进行一项研究，以确定不同磁几何形状区域之间的流场差异。

The solar wind plasma within 20 Ro will be studied using a variety of radio propagation techniques. This will permit estimation of the spatial spectrum of density fluctuations, the mean flow velocity, its random component and the orientation of the magnetic field. These measurements will be compared with optical data, such as white light coronograph, magnetograph, and emission line observations. The basic objectives will be to learn more about the mechanism of coronal heating and the flow of energy near the critical point, and to study the coronal origin of large scale structures such as fast streams. Within 20 Ro earlier observations have shown a rapid increase in random velocity, excess power in density fluctuations on scales of 10 to 300 km, and density fluctuations which become highly isotropic. This study will measure the acceleration of the particles through the sonic point using multiple antenna intensity scintillations. The spatial anisotropy as a function of spatial scale will be measured by comparing angular scattering (measured at the VLA) with phase scintillation (measured with the VLBA). The intensity scintillations will be analyzed to learn the origin of the random velocity component. Finally, observations within 20 Ro can be compared with surface measurements more accurately than those further from the sun because the mapping distance is small and stream-stream interactions are much less important. A study will be made to determine the difference in the flow field between regions of different magnetic geometry.