Surfatron and stochastic acceleration of electrons in astrophysical plasmas

Details Surfatron and stochastic acceleration of electrons in astrophysical plasmas Surfatron and stochastic acceleration of electrons in astrophysical plasmas

Apr 2005

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005jplph..71..127m&link_type=abstract

Journal of Plasma Physics, vol. 71, Issue 2, p.127-141

Physics

Plasma Physics

1

Scientific paper

Electron acceleration by large amplitude electrostatic waves in astrophysical plasmas is studied using particle-in-cell (PIC) simulations. The waves are excited initially at the electron plasma frequency ωpe by a Buneman instability driven by ion beams: the parameters of the ion beams are appropriate for high Mach number astrophysical shocks, such as those associated with supernova remnants (SNRs). If ωpe is much higher than the electron cyclotron frequency Ωe, the linear phase of the instability does not depend on the magnitude of the magnetic field. However, the subsequent time evolution of particles and waves depends on both ωpe/Ωe and the size of the simulation box L. If L is equal to one wavelength, λ0, of the Buneman-unstable mode, electrons trapped by the waves undergo acceleration via the surfatron mechanism across the wave front. This occurs most efficiently when ωpe/Ωe ≃ 100: in this case electrons are accelerated to speeds of up c/2 where c is the speed of light. In a simulation with L=4λ0 and ωpe/Ωe = 100, it is found that sideband instabilities give rise to a broad spectrum of wavenumbers, with a power law tail. Some stochastic electron acceleration is observed in this case, but not the surfatron process. Direct integration of the electron equations of motion, using parameters approximating to those of the wave modes observed in the simulations, suggests that the surfatron is compatible with the presence of a broad wave spectrum if ωpe/Ωe> 100. It is concluded that a combination of stochastic and surfatron acceleration could provide an efficient generator of mildly relativistic electrons at SNR shocks.

Affiliated with

Also associated with

No associations

Rating

Surfatron and stochastic acceleration of electrons in astrophysical plasmas does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Surfatron and stochastic acceleration of electrons in astrophysical plasmas, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Surfatron and stochastic acceleration of electrons in astrophysical plasmas will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-976455