Fermi acceleration

2006 ◽  
pp. 231-240 ◽  
Author(s):  
Luke O'C. Drury
Keyword(s):  
Fermi Acceleration

Evidence of Fermi Acceleration of Lyα in the Radio Galaxy 1243+036

1998 ◽  
Vol 505 (2) ◽  
pp. 634-638 ◽  
Author(s):  
Luc Binette ◽  
Benoit Joguet ◽  
John C. L. Wang
Keyword(s):  
Radio Galaxy ◽  
Fermi Acceleration

Stochastic Fermi acceleration of ions in the pre-shock region of comet P/Halley

1988 ◽  
pp. 293-296
Author(s):  
B. E. Gribov ◽  
K. Kecskeméty ◽  
R. Z. Sagdeev ◽  
V. D. Shapiro ◽  
V. I. Shevchenko ◽  
...  
Keyword(s):  
Fermi Acceleration ◽  
Shock Region

scholarly journals Investigating 1st and 2nd order Fermi acceleration of energetic particles by small-scale magnetic flux ropes at 1AU

2020 ◽  
Vol 1620 ◽  
pp. 012008
Author(s):  
J A le Roux ◽  
G M Webb ◽  
O V Khabarova ◽  
K T Van Eck ◽  
L-L Zhao ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Energetic Particles ◽  
Small Scale ◽  
Fermi Acceleration ◽  
Magnetic Flux Ropes ◽  
Flux Ropes

scholarly journals Mechanisms for Flash Phase Phenomena in Solar Flares

1974 ◽  
Vol 57 ◽  
pp. 253-282 ◽  
Author(s):  
Dean F. Smith
Keyword(s):  
Solar Flares ◽  
Acoustic Waves ◽  
Plasma Waves ◽  
Electron Plasma ◽  
X Rays ◽  
Fermi Acceleration ◽  
Acceleration Region ◽  
Low Frequencies ◽  
Coulomb Collisions ◽  
The Earth

Mechanisms for explaining the various forms of particles and radiation observed during the flash phase of solar flares are reviewed under the working hypothesis that the flash phase is the time in which electrons and to a lesser degree protons are accelerated in less than one second. A succession of such accelerations is allowed to explain longer lasting or quasi-periodic phenomena. Mechanisms capable of such acceleration are reviewed and it is concluded that first-order Fermi acceleration in a reconnecting current sheet is the most likely basic process. Such acceleration, however, gives rise to a rather narrow distribution of particle velocities along a given field line which is unstable to the production of electron plasma and ion-acoustic waves. This plasma turbulence can heat the plasma to produce soft X-rays and filter the initially narrow velocity distribution to produce a power law energy distribution. Electrons travelling inward from the acceleration region produce hard X-rays by bremsstrahlung and microwave bursts by gyro-synchrotron emission. Whereas the interpretation of X-ray spectra is relatively straightforward, the interpretation of microwave spectra is difficult because the source at low frequencies can be made optically thick by several different mechanisms.Electrons travelling further inward presumably thermalize and produce impulsive EUV and Hα emission. The theory for these emissions, although amenable to present techniques in radiative transfer, has not been worked out. Electrons travelling outward give rise to type III radio bursts by excitation of electron plasma waves and the electrons observed at the Earth. Study of the interaction of a stream of electrons with the ambient plasma shows that the electron spectra observed at the Earth do not necessarily reflect their spectrum at the acceleration region since they interact via plasma waves as well as through Coulomb collisions. The mechanisms for the conversion of plasma waves into radiation and the propagation of the radiation from its source to the observer are reviewed.

Sign in / Sign up

Export Citation Format

Share Document