Debye length and plasma skin depth: two length scales of interest in the creation and diagnosis of laboratory pair plasmas

Stenson, E. V.; Horn-Stanja, J.; Stoneking, M. R.; Pedersen, T. S.

doi:10.1017/s0022377817000022

Cited by 55 publications

(50 citation statements)

References 49 publications

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“…These frequency is well below the plasma frequency of the companion photosphere, νp 7 × 10 6 ρ 1/2 (X + Y /2) 1/2 GHz, where ρ is the density of the photosphere, and X and Y represent the hydrogen and helium mass fraction, respectively. In this situation plasma behaves has a metal almost entirely reflecting the impinging radiation (see e.g., Stenson et al 2017), which is therefore unable to effectively penetrate the external layers of the companion and power the GQC mechanism. In line with the Goldreich and Julian model (see Goldreich & Julian 1969, Hirotani 2006 and references therein), the remaining power, still of the order of ×10 32 erg s −1 , is emitted in the form of high energy gamma rays and electron-positron relativistic pairs.…”

Section: Gravitation Quadrupole Couplingmentioning

confidence: 99%

On the timing properties of SAX J1808.4−3658 during its 2015 outburst

Sanna

Salvo

Burderi

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present a timing analysis of the 2015 outburst of the accreting millisecond Xray pulsar SAX J1808.4-3658, using non-simultaneous XMM-Newton and NuSTAR observations. We estimate the pulsar spin frequency and update the system orbital solution. Combining the average spin frequency from the previous observed, we confirm the long-term spin down at an average rateν SD = 1.5(2) × 10 −15 Hz s −1 . We also discuss possible corrections to the spin down rate accounting for mass accretion onto the compact object when the system is X-ray active. Finally, combining the updated ephemerides with those of the previous outbursts, we find a long-term orbital evolution compatible with a binary expansion at a mean rateṖ orb = 3.6(4) × 10 −12 s s −1 , in agreement with previously reported values. This fast evolution is incompatible with an evolution driven by angular momentum losses caused by gravitational radiation under the hypothesis of conservative mass transfer. We discuss the observed orbital expansion in terms of non-conservative mass transfer and gravitational quadrupole coupling mechanism. We find that the latter can explain, under certain conditions, small fluctuations (of the order of few seconds) of the orbital period around a global parabolic trend. At the same time, a non-conservative mass transfer is required to explain the observed fast orbital evolution, which likely reflects ejection of a large fraction of mass from the inner Lagrangian point caused by the irradiation of the donor by the magneto-dipole rotator during quiescence (radio-ejection model). This strong outflow may power tidal dissipation in the companion star and be responsible of the gravitational quadrupole change oscillations.

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Section: Gravitation Quadrupole Couplingmentioning

confidence: 99%

On the timing properties of SAX J1808.4−3658 during its 2015 outburst

Sanna

Salvo

Burderi

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…These objects have recently been gathering increasing interest in the academic community, not only for their unique properties (see for instance, Ref. [1]) but also for the major role they play in the dynamics of a wide range of extreme astrophysical objects. For instance, magnetized electronpositron plasmas exist in pulsar magnetospheres [2], in bipolar outflows in active galactic nuclei [3], at the center of our own galaxy [4], and in the early universe [5].…”

Section: Introductionmentioning

confidence: 99%

General features of experiments on the dynamics of laser-driven electron–positron beams

Warwick

Alejo

Dzelzainis

et al. 2018

Nuclear Instruments and Methods in Physics Research Section A:

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The experimental study of the dynamics of neutral electron-positron beams is an emerging area of research, enabled by the recent results on the generation of this exotic state of matter in the laboratory. Electron-positron beams and plasmas are believed to play a major role in the dynamics of extreme astrophysical objects such as supermassive black holes and pulsars. For instance, they are believed to be the main constituents of a large number of astrophysical jets, and they have been proposed to significantly contribute to the emission of gamma-ray bursts and their afterglow. However, despite extensive numerical modelling and indirect astrophysical observations, a detailed experimental characterisation of the dynamics of these objects is still at its infancy. Here, we will report on some of the general features of experiments studying the dynamics of electron-positron beams in a fully laserdriven setup.

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“…35.Qz,98.62.Nx The exact symmetry between its positively and negatively charged constituents makes electron-positron plasmas and beams (EPBs) unique cases in plasma physics. For instance, the exact mobility of the two species forbids the excitation of drift and acoustic modes [1], and, more generally, EPBs have a much more simplified Clemmow-Mullaly-Allis diagram than that of their electron-ion counterpart (see, for instance, [2]). EPBs are also believed to play a central role in a range of high-energy astrophysical phenomena, such as the ultra-relativistic outflows from active galactic nuclei and pulsars [3][4][5][6].…”

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confidence: 99%

Experimental Observation of a Current-Driven Instability in a Neutral Electron-Positron Beam

et al. 2017

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We report on the first experimental observation of a current-driven instability developing in a quasineutral matter-antimatter beam. Strong magnetic fields (amp;gt;= 1 T) are measured, via means of a proton radiography technique, after the propagation of a neutral electron-positron beam through a background electron-ion plasma. The experimentally determined equipartition parameter of epsilon(B) approximate to 10(-3) is typical of values inferred from models of astrophysical gamma-ray bursts, in which the relativistic flows are also expected to be pair dominated. The data, supported by particle-in-cell simulations and simple analytical estimates, indicate that these magnetic fields persist in the background plasma for thousands of inverse plasma frequencies. The existence of such long-lived magnetic fields can be related to analog astrophysical systems, such as those prevalent in lepton-dominated jets.

Funding Agencies|EPSRC [EP/N022696/1, EP/N027175/1, EP/L013975/1, EP/N002644/1, EP/P010059/1]; DOE [DE-NA0002372]; ARO [W911NF-16-1-0044]

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Debye length and plasma skin depth: two length scales of interest in the creation and diagnosis of laboratory pair plasmas

Cited by 55 publications

References 49 publications

On the timing properties of SAX J1808.4−3658 during its 2015 outburst

On the timing properties of SAX J1808.4−3658 during its 2015 outburst

General features of experiments on the dynamics of laser-driven electron–positron beams

Experimental Observation of a Current-Driven Instability in a Neutral Electron-Positron Beam

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