期刊
SPACE SCIENCE REVIEWS
卷 173, 期 1-4, 页码 535-556出版社
SPRINGER
DOI: 10.1007/s11214-012-9900-6
关键词
Particle acceleration
资金
- NSF
- NASA [NNX10AC06G]
- NASA [136333, NNX10AC06G] Funding Source: Federal RePORTER
The subject of this paper is stochastic acceleration by plasma turbulence, a process akin to the original model proposed by Fermi. We review the relative merits of different acceleration models, in particular the so called first order Fermi acceleration by shocks and second order Fermi by stochastic processes, and point out that plasma waves or turbulence play an important role in all mechanisms of acceleration. Thus, stochastic acceleration by turbulence is active in most situations. We also show that it is the most efficient mechanism of acceleration of relatively cool non relativistic thermal background magnetized plasma particles. In addition, it can preferentially accelerate electrons relative to protons as is needed in many astrophysical radiating sources, where usually there are no indications of presence of shocks. We also point out that a hybrid acceleration mechanism consisting of initial acceleration by turbulence of background particles followed by a second stage acceleration by a shock has many attractive features. It is demonstrated that the above scenarios can account for many signatures of the accelerated electrons, protons and other ions, in particular He-3 and He-4, seen directly as Solar Energetic Particles and through the radiation they produce in solar flares.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据