Stochastic Acceleration by Turbulence

By V. Petrosian. 2012

164 citations recorded by the source corpus.

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 3He and 4He, seen directly as Solar Energetic Particles and through the radiation they produce in solar flares.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/9cb7e38450c150d074003b7484088903c204fe5a

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. L. Sironi
2. Bernhard Fleck
3. R. Marsden
4. L. Comisso
5. A. Spitkovsky
6. D. Giannios
7. M. Petropoulou
8. J. Arons

In Nuclear and High Energy Physics

1. L. Sironi
2. Bernhard Fleck
3. R. Marsden
4. L. Comisso
5. A. Spitkovsky
6. D. Giannios
7. M. Petropoulou
8. J. Arons

Citations in the corpus

• The Solar Orbiter mission (2020, background): “…involves particles repeatedly interacting with moving or turbulent magnetic field, gaining small amounts of energy at each step, and is believed to operate in shock waves and in regions of high turbulence (see e.g. reviews of the mechanism physics by Petrosian (2012) and Zhang & Lee (2013)).”
• The Interplay of Magnetically Dominated Turbulence and Magnetic Reconnection in Producing Nonthermal Particles (2019, background): “Among such mechanisms, plasma turbulence has been often invoked to explain nonthermal particles in a variety of astrophysical systems (e.g. Melrose 1980; Petrosian 2012; Lazarian et al. 2012).”