The Accleration and Transport of Particles Energized in Solar Flares and in the Interplanetary Medium

高能粒子研究可以提供对日地物理许多重要过程的基本见解。例如，大耀斑中太阳高能粒子的元素组成产生了日冕的组成，并且在某种程度上与光球层的组成有系统地不同，这取决于元素的第一电离势。这种相关性对于理解重离子从光球层到日冕的传输是至关重要的。作为另一个例子，在太阳系的许多地点，包括日冕和行星际介质，都发生了激波激发粒子的现象，这为研究不同大小和时间尺度区域中的粒子加速提供了机会。作为最后一个例子，高能粒子通过湍流星际介质从太阳到地球的传输，以及激波加速粒子的传输，使我们能够深入了解太阳风等离子体在非常不同的湍流级别下的等离子体特性。这笔NSF赠款将利用马里兰大学现有的计算机和程序库以及大型数据集来研究一些太阳和星际物理问题，在许多情况下，最好的办法是利用统计调查和/或多航天器观测来解决这些问题。用于这项研究的马里兰IMP、ISEE和Voyager上的仪器能够区分低能粒子群中的不同离子物种，使研究高能粒子现象的独特方面成为可能。将开展的具体研究包括：1)将使用详细的粒子输运研究小型冲激太阳耀斑中的太阳粒子加速和输运。2)将利用粒子组成信息研究行星际激波加速过程，以比较激波加速粒子群和候选种子群，如太阳耀斑粒子。3)行星际激波中的上游扩散系数将使用梯度技术从粒子数据中得到。4)描述了激波加速粒子群在1~4-5AU之间的径向演化。5)行星际介质中的加速过程产生了反常的宇宙线分量，并将探讨彗星附近湍流区的加速离子。

Energetic particle studies can provide essential insights into many processes of importance to solar-terrestrial physics. For example, the elemental composition of solar energetic particles in large flares yields the composition of the solar corona, and is systematically different from the photospheric composition in a manner depending on the first ionization potential of the element. This dependence is of key importance in understanding the transport of heavy ions from the photosphere to the corona. As another example, particle energization by shock waves occurs at many sites in the solar system including the corona and the interplanetary medium, offering the opportunity to study particle acceleration in regions with different sizes and time scales. As a final example, the transport of energetic particles from the sun to the earth through the turbulent interplanetary medium, and the transport of shock accelerated particles give insights into the plasma properties of the solar wind plasma under widely differing levels of turbulence. This NSF grant will take advantage of the existing computers and program libraries, and large data sets at the University of Maryland to investigate a number of solar and interplanetary physics problems which in many cases can be best attacked using statistical surveys and/or multi-spacecraft observations. The Maryland instrument on IMP, ISEE, and Voyager used for this study is able to distinguish different ionic species in low energy particle populations, making it possible to investigate unique aspects of energetic particle phenomena. Specific studies to be undertaken include: 1) Solar particle acceleration and transport in small, impulsive solar flares will be investigated using a detailed particle transport. 2) Interplanetary shock acceleration processes will be studied using particle composition information to compare the shock accelerated particle population with candidate seed populations such as solar flare particles. 3) Upstream diffusion coefficients in interplanetary shocks will be derived from particle data using gradient techniques. 4) The radial evolution of shock accelerated particle populations between 1 and 4-5 AU will be characterized. 5) Acceleration processes in the interplanetary medium produce the Anomalous Cosmic Ray component and accelerate ions in the turbulent regions near comets will be probed.