arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0903.2576astro-ph.SRastro-ph.EPastro-ph.HE
收藏

在地球附近观测到的脉冲太阳高能电子事件的起始和光谱

Onsets and spectra of impulsive solar energetic electron events observed near the Earth

E. P. Kontar, H. A. S. Reid

摘要:

脉冲太阳高能电子经常在地球附近的行星际空间被观测到,并且对于知之甚少的太阳耀斑加速过程具有吸引人的诊断潜力。我们研究了太阳耀斑高能电子在日球等离子体中的输运,以了解输运对观测到的脉冲太阳电子事件的发生和光谱特性的作用。考虑静电电子等离子体(Langmuir)波的自洽产生和吸收、非均匀等离子体效应、碰撞和朗道阻尼,模拟了高能电子在太阳风等离子体中从太阳加速区到地球的传播过程。模拟结果表明,束流驱动的等离子体湍流和太阳风密度不均匀性的影响起着至关重要的作用,并导致出现以下现象:a)单一幂律注入电子谱的谱突变,谱突变下方的谱变平坦; b)低能电子注入的明显早期开始; c)低能电子注入的明显晚期最大值。我们发现,所观察到的发病,在低能量的光谱平坦化,并在几十keV的断裂能量的形成是波-粒子相互作用的非均匀等离子体中的一个单一的加速电子人口与初始的幂律谱的直接表现。

英文摘要:

Impulsive solar energetic electrons are often observed in the interplanetary space near the Earth and have an attractive diagnostic potential for poorly understood solar flare acceleration processes. We investigate the transport of solar flare energetic electrons in the heliospheric plasma to understand the role of transport to the observed onset and spectral properties of the impulsive solar electron events. The propagation of energetic electrons in solar wind plasma is simulated from the acceleration region at the Sun to the Earth, taking into account self-consistent generation and absorption of electrostatic electron plasma (Langmuir) waves, effects of non-uniform plasma, collisions and Landau damping. The simulations suggest that the beam-driven plasma turbulence and the effects of solar wind density inhomogeneity play a crucial role and lead to the appearance of a) spectral break for a single power-law injected electron spectrum, with the spectrum flatter below the break, b) apparent early onset of low-energy electron injection, c) the apparent late maximum of low-energy electron injection. We show that the observed onsets, spectral flattening at low energies, and formation of a break energy at tens of keV is the direct manifestation of wave-particle interactions in non-uniform plasma of a single accelerated electron population with an initial power-law spectrum.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑