Simulation study of surfing acceleration in magnetized space plasmas

Eliasson, Bengt; Dieckmann, Mark E; Shukła, P. K.

doi:10.1088/1367-2630/7/1/136

Cited by 16 publications

(18 citation statements)

References 24 publications

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“…We find that the ESWs moving at nonrelativistic phase speeds saturate smoothly, which is in line with the wave saturation of the ESW in the Vlasov simulation in Dieckmann et al (2004b). Their lifetime is significant and, in the presence of a weak external magnetic field B orthogonal to the wave vector k, the trapped electrons would undergo substantial ESA (Eliasson et al 2005). The ESA is proportional to v ph |B| and the comparatively low v ph would limit the maximum energy the electrons can reach.…”

Section: Wave Collapse and Secondary Electron Trappingsupporting

confidence: 82%

“…Initially a stable non-linear wave known as BGK mode (Bernstein et al 1957;Manfredi 1997;Brunetti et al 2000) develops if the plasma is unmagnetised or if the magnetic field is weak (McClements et al 2001;Dieckmann et al 2002;Eliasson et al 2005). Such modes are associated with phase space holes -islands of trapped electrons.…”

Section: Introductionmentioning

confidence: 99%

“…BGK modes) are destabilised by the noise (Schamel & Korn 1996) and may benefit from a plasma model based on the direct solution of the Vlasov equation. Such effects have been demonstrated in the non-relativistic limit, for example by Eliasson et al (2005) and Dieckmann et al (2004b), in which the results computed by PIC codes have been compared to those of Vlasov codes. The particle species in a Vlasov code are represented by a continuous distribution function, conventionally evolved on a fixed Eulerian grid, rather than by simulation macro-particles.…”

Section: Introductionmentioning

confidence: 99%

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Stabilisation of BGK modes by relativistic effects

Sircombe¹,

Dieckmann²,

Shukła³

et al. 2006

A&A

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Context. We examine plasma thermalisation processes in the foreshock region of astrophysical shocks within a fully kinetic and self-consistent treatment. We concentrate on proton beam driven electrostatic processes, which are thought to play a key role in the beam relaxation and the particle acceleration. Our results have implications for the effectiveness of electron surfing acceleration and the creation of the required energetic seed population for first order Fermi acceleration at the shock front. Aims. We investigate the acceleration of electrons via their interaction with electrostatic waves, driven by the relativistic Buneman instability, in a system dominated by counter-propagating proton beams. Methods. We adopt a kinetic Vlasov-Poisson description of the plasma on a fixed Eulerian grid and observe the growth and saturation of electrostatic waves for a range of proton beam velocities, from 0.15c to 0.9c. Results. We can report a reduced stability of the electrostatic wave (ESW) with increasing non-relativistic beam velocities and an improved wave stability for increasing relativistic beam velocities, both in accordance with previous findings. At the highest beam speeds, we find the system to be stable again for a period of ≈160 plasma periods. Furthermore, the high phase space resolution of the Eulerian Vlasov approach reveals processes that could not be seen previously with PIC simulations. We observe a, to our knowledge, previously unreported secondary electron acceleration mechanism at low beam speeds. We believe that it is the result of parametric couplings to produce high phase velocity ESW's which then trap electrons, accelerating them to higher energies. This allows electrons in our simulation study to achieve the injection energy required for Fermi acceleration, for beam speeds as low as 0.15c in unmagnetised plasma.

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Section: Wave Collapse and Secondary Electron Trappingsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Stabilisation of BGK modes by relativistic effects

Sircombe¹,

Dieckmann²,

Shukła³

et al. 2006

A&A

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“…Although wave-particle interactions play a major role in the physics of ionized matter, the nature of this complex interaction in plasmas has predominantly been investigated theoretically and by simulations. [1][2][3][4][5][6] One reason for this is that the spatio-temporal complexities of the underlying phenomena require experimental investigations using highly sophisticated diagnostics. Recent advances in optical diagnostics with high temporal resolution have made detailed investigations possible.…”

mentioning

confidence: 99%

Plasma ionization through wave-particle interaction in a capacitively coupled radio-frequency discharge

O’Connell

Gans

Vender³

et al. 2007

Physics of Plasmas

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Phase resolved optical emission spectroscopy, with high temporal resolution, shows that wave-particle interactions play a fundamental role in sustaining capacitively coupled rf plasmas. The measurements are in excellent agreement with a simple particle-in-cell simulation. Excitation and ionization mechanisms are dominated by beam-like electrons, energized through the advancing and retreating electric fields of the rf sheath. The associated large-amplitude electron waves, driven by a form of two-stream instability, result in power dissipation through electron trapping and phase mixing.

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“…In contrast, ESA works best for weak magnetic fields, at least for non‐relativistic wave speeds (Eliasson, Dieckmann & Shukla 2005), and could function even with the weak magnetic fields of the outer accretion disc (Jones et al 2001). We focus here on weak magnetic fields by which we probably exclude processes taking place in the jet‐formation region.…”

Section: Simulation Set‐upmentioning

confidence: 99%

Electron surfing acceleration in oblique magnetic fields

Dieckmann

Eliasson

Parviainen

et al. 2006

Monthly Notices of the Royal Astronomical Society

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Initially, inhomogeneous plasma jets, ejected by active galactic nuclei and associated with gamma-ray bursts, are thermalized by the formation of internal shocks. Jet subpopulations can hereby collide at Lorentz factors of a few. As the resulting relativistic shock expands into the upstream plasma, a significant fraction of the upstream ions is reflected. These ions, together with downstream ions that leak through the shock, form relativistic beams of ions that outrun the shock. The thermalization of these beams via the two-stream instability is thought to contribute significantly to plasma heating and particle acceleration by the shock. Here, the capability of a two-stream instability to generate relativistic field-aligned and cross-field electron flow, is examined for a magnetized plasma by means of a particle-in-cell (PIC) simulation. The electrons interact with the developing quasi-electrostatic waves and oblique magnetic fields. The simulation results bring forward evidence that such waves, by their non-linear interactions with the plasma, produce a highly relativistic field-aligned electron flow and electron energies, which could contribute to the radio synchrotron emissions from astrophysical jets, to ultrarelativistic leptonic subpopulations propagating with the jet and to the halo particles surrounding the accretion disc of the black hole

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Simulation study of surfing acceleration in magnetized space plasmas

Cited by 16 publications

References 24 publications

Stabilisation of BGK modes by relativistic effects

Stabilisation of BGK modes by relativistic effects

Plasma ionization through wave-particle interaction in a capacitively coupled radio-frequency discharge

Electron surfing acceleration in oblique magnetic fields

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