Particle Acceleration in Solar Flares

太阳耀斑中的粒子加速

• 批准号: 9214678
• 负责人: Dean Smith
• 金额: $ 17.79万
• 依托单位: Berkeley Research Associates Inc
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-03-01 至 1997-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9214678&HistoricalAwards=false
• 关键词: Particle; Acceleration; Solar; Flares

This project will study particle acceleration in solar flares. A key problem in solar flare physics is the manner in which protons and other particles are accelerated to several tens of MeV in a few seconds as evidenced by impulsive >-ray emission. This process is called first-phase ion acceleration. The most widely accepted models in explaining this acceleration are shock acceleration and stochastic acceleration by Alfven or magnetosonic waves. Neither of these models has been developed self-consistently or has direct observational verification. This project examines the consistent development of a single-loop manetohydrodynamic (MHD) wave stochastic acceleration model. A half-loop is divided into 2 coronal sections attached to a model chromosphere and photosphere. The coronal sections include the source where time-dependent acceleration including wave-particle and wave-wave interactions occurs, and a transport section in which protons propagate diffusively. Unlike previous work, it will be a complete model for nonrelativistic energies including a nuclear interaction calculation. Thus, it will be possible to study the effect of changing the spectrum and/or power of turbulence in the source, the loop size, etc., throughout the whole loop. In short, we shall be able to put the stochastic acceleration model to a very thorough test. Observational consequences in prompt >-ray emission come from the nuclear interaction part of the calculation. These results will increase our understanding in this important area of solar research. #

该项目将研究太阳耀斑中的粒子加速。 太阳耀斑物理学的一个关键问题是质子和其他粒子在几秒钟内加速到几十兆电子伏的方式，如脉冲射线发射所证明的那样。这个过程称为第一相离子加速。解释这种加速度最广泛接受的模型是冲击加速度和阿尔文波或磁声波的随机加速度。这些模型都不是自洽开发的，也没有直接的观测验证。该项目研究了单环动流体动力学 (MHD) 波随机加速模型的持续发展。半环分为 2 个冠状部分，连接到模型色球层和光球层。 日冕部分包括发生与时间相关的加速度（包括波-粒子和波-波相互作用）的源，以及质子在其中扩散传播的传输部分。与之前的工作不同，它将是一个完整的非相对论能量模型，包括核相互作用计算。因此，可以研究改变整个环路中源中湍流的频谱和/或功率、环路尺寸等的影响。简而言之，我们将能够对随机加速模型进行非常彻底的测试。瞬发射线发射的观测结果来自计算的核相互作用部分。这些结果将增加我们对太阳能研究这一重要领域的理解。 #