The effect of parallel electric field in shock waves on the acceleration of relativistic ions, electrons, and positrons

2009 ◽  
Vol 16 (11) ◽  
pp. 112308 ◽  
Author(s):  
Seiichi Takahashi ◽  
Hiromasa Kawai ◽  
Yukiharu Ohsawa ◽  
Shunsuke Usami ◽  
Charles Chiu ◽  
...  
Keyword(s):  
Shock Waves ◽  
Electric Field ◽  
Parallel Electric Field ◽  
Electrons And Positrons

Erratum: “The effect of parallel electric field in shock waves on the acceleration of relativistic ions, electrons, and positrons” [Phys. Plasmas 16, 112308 (2009)]

2009 ◽  
Vol 16 (12) ◽  
pp. 129904
Author(s):  
Seiichi Takahashi ◽  
Hiromasa Kawai ◽  
Yukiharu Ohsawa ◽  
Shunsuke Usami ◽  
Charles Chiu ◽  
...  
Keyword(s):  
Shock Waves ◽  
Electric Field ◽  
Parallel Electric Field ◽  
Electrons And Positrons

Nonlinear low-frequency structures in an electron–positron–ion plasma

2012 ◽  
Vol 78 (5) ◽  
pp. 545-551 ◽  
Author(s):  
S. MOOLLA ◽  
I. J. LAZARUS ◽  
R. BHARUTHRAM
Keyword(s):  
Electric Field ◽  
Acoustic Waves ◽  
Rest Frame ◽  
Low Frequency ◽  
Satellite Observations ◽  
Parallel Electric Field ◽  
Ion Acoustic Waves ◽  
Ion Plasma ◽  
Electron Positron ◽  
Electrons And Positrons

AbstractNonlinear ion cyclotron and ion-acoustic waves have been studied in an electron–positron–ion plasma. Using Boltzmann distributions for the electrons and positrons and fluid equations for the ions, a set of nonlinear equations in the rest frame of the propagating wave is derived and numerically solved for the electric field. A scan of parameter space reveals a range of solutions for the parallel electric field, from sinusoidal to sawtooth to highly spiky waveforms. The results are compared with satellite observations.

scholarly journals Double layers in the downward current region of the aurora

2003 ◽  
Vol 10 (1/2) ◽  
pp. 45-52 ◽  
Author(s):  
R. E. Ergun ◽  
L. Andersson ◽  
C. W. Carlson ◽  
D. L. Newman ◽  
M. V. Goldman
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Phase Space ◽  
Electric Field ◽  
Electric Fields ◽  
Double Layers ◽  
Parallel Electric Field ◽  
Electrostatic Waves ◽  
Current Region ◽  
Decisive Evidence

Abstract. Direct observations of magnetic-field-aligned (parallel) electric fields in the downward current region of the aurora provide decisive evidence of naturally occurring double layers. We report measurements of parallel electric fields, electron fluxes and ion fluxes related to double layers that are responsible for particle acceleration. The observations suggest that parallel electric fields organize into a structure of three distinct, narrowly-confined regions along the magnetic field (B). In the "ramp" region, the measured parallel electric field forms a nearly-monotonic potential ramp that is localized to ~ 10 Debye lengths along B. The ramp is moving parallel to B at the ion acoustic speed (vs) and in the same direction as the accelerated electrons. On the high-potential side of the ramp, in the "beam" region, an unstable electron beam is seen for roughly another 10 Debye lengths along B. The electron beam is rapidly stabilized by intense electrostatic waves and nonlinear structures interpreted as electron phase-space holes. The "wave" region is physically separated from the ramp by the beam region. Numerical simulations reproduce a similar ramp structure, beam region, electrostatic turbulence region and plasma characteristics as seen in the observations. These results suggest that large double layers can account for the parallel electric field in the downward current region and that intense electrostatic turbulence rapidly stabilizes the accelerated electron distributions. These results also demonstrate that parallel electric fields are directly associated with the generation of large-amplitude electron phase-space holes and plasma waves.

Relationship between Field-Aligned Currents and Parallel Electric Field Observed by Akebono

1998 ◽  
pp. 59-62 ◽  
Author(s):  
M. Morooka ◽  
T. Yamamoto ◽  
T. Mukai ◽  
K. Tsuruda ◽  
H. Hayakawa ◽  
...  
Keyword(s):  
Electric Field ◽  
Parallel Electric Field

scholarly journals Relativistic Particle Acceleration in Plerions

1994 ◽  
Vol 142 ◽  
pp. 797-806
Author(s):  
Jonathan Arons ◽  
Marco Tavani
Keyword(s):  
Magnetic Field ◽  
Particle Acceleration ◽  
Shock Waves ◽  
Shock Front ◽  
Heavy Ions ◽  
Surface Brightness ◽  
Crab Nebula ◽  
Electrons And Positrons ◽  
The Crab Nebula ◽  
The Magnetic Field

AbstractWe discuss recent research on the structure and particle acceleration properties of relativistic shock waves in which the magnetic field is transverse to the flow direction in the upstream medium, and whose composition is either pure electrons and positrons or primarily electrons and positrons with an admixture of heavy ions. Particle-in-cell simulation techniques as well as analytic theory have been used to show that such shocks in pure pair plasmas are fully thermalized—the downstream particle spectra are relativistic Maxwellians at the temperature expected from the jump conditions. On the other hand, shocks containing heavy ions which are a minority constituent by number but which carry most of the energy density in the upstream medium do put ~20% of the flow energy into a nonthermal population of pairs downstream, whose distribution in energy space is N(E) ∝ E−2, where N(E)dE is the number of particles with energy between E and E + dE.The mechanism of thermalization and particle acceleration is found to be synchrotron maser activity in the shock front, stimulated by the quasi-coherent gyration of the whole particle population as the plasma flowing into the shock reflects from the magnetic field in the shock front. The synchrotron maser modes radiated by the heavy ions are absorbed by the pairs at their (relativistic) cyclotron frequencies, allowing the maximum energy achievable by the pairs to be γ±m±c2 = mic2γ1/Zi, where γ1 is the Lorentz factor of the upstream flow and Zi, is the atomic number of the ions. The shock’s spatial structure is shown to contain a series of “overshoots” in the magnetic field, regions where the gyrating heavy ions compress the magnetic field to levels in excess of the eventual downstream value.This shock model is applied to an interpretation of the structure of the inner regions of the Crab Nebula, in particular to the “wisps,” surface brightness enhancements near the pulsar. We argue that these surface brightness enhancements are the regions of magnetic overshoot, which appear brighter because the small Larmor radius pairs are compressed and radiate more efficiently in the regions of more intense magnetic field. This interpretation suggests that the structure of the shock terminating the pulsar’s wind in the Crab Nebula is spatially resolved, and allows one to measure γ1, and a number of other properties of the pulsar’s wind. We also discuss applications of the shock theory to the termination shocks of the winds from rotation-powered pulsars embedded in compact binaries. We show that this model adequately accounts for (and indeed predicted) the recently discovered X-ray flux from PSR 1957+20, and we discuss several other applications to other examples of these systems.Subject headings: acceleration of particles — ISM: individual (Crab Nebula) — relativity — shock waves

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