Non-stationary pair plasma in a pulsar magnetosphere and the two-stream Instability

Asséo, E.; Melikidze, George I.

doi:10.1046/j.1365-8711.1998.01990.x

Cited by 110 publications

(147 citation statements)

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“…This mechanism is consistent with other forms of indirect radiation mechanisms, where primary effects generate secondary electromagnetic effects (Melrose 1993;Asseo & Melikidze 1998;Melikidze et al 2000;Asseo & Riazuelo 2000). There are however two main differences.…”

Section: Introductionsupporting

confidence: 86%

“…Second, the primary process is not strictly thermal, as seen in Paper I, but it might be a stochastic perturbation induced in the rest frame either directly by the quasiclassical process as described by da Costa & Kahn (1997), or other possible phenomena, as the presence of complex non-thermal plasma density distribution functions which will act to produce non-thermal phenomena similar to the one described by Asseo & Melikidze (1998).…”

Section: Introductionmentioning

confidence: 99%

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Coupling between electrostatic and electromagnetic behaviour in a cylindrical equal-mass plasma

Diver

Costa²,

Laing

2002

A&A

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Abstract. The electron-positron plasma present in pulsar magnetospheres may have non-linear electrostatic oscillations, which can couple to electromagnetic waves if the magnetic field present is inhomogeneous. Using a cylindrical geometry the basic equations are derived, and using a simplified linear approach characteristic linear modes are identified and analysed. A possible coupling mechanism is discussed, and possible consequences for pulsar radiation mechanisms are inferred.

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Section: Introductionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Coupling between electrostatic and electromagnetic behaviour in a cylindrical equal-mass plasma

Diver

Costa²,

Laing

2002

A&A

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“…Usov (1987) first pointed out that the nonstationarity associated with sparking discharges naturally leads to a two-stream instability as the result of mutual penetration between the slower and the faster plasma components. Asseo & Melikidze (1998) developed this idea further, calculated the growth rates, and demonstrated that the instability is very efficient in generating Langmuir plasma waves at distances of many stellar radii r ins $ 10 4 À10 5 ð Þ h CR ¼ 10 7 À10 8 cm, where h CR is the height of the acceleration region described by equation (21) (Melikidze et al 2000). This is exactly where pulsar's radio emission is supposed to originate (e.g., Kijak & Gil 1998).…”

Section: Discussionmentioning

confidence: 99%

“…[1]). Then the spark plasma escapes from the region, as discussed by Asseo & Melikidze (1998). However, during a short escaping timescale h/c $ 10 À8 s the thermionic ions still maintain the partial screening as determined by equation (6).…”

Section: Charge-depleted Inner Acceleration Regionmentioning

confidence: 96%

“…Moreover, some electrons and positrons from the outflowing spark plasma column would still be near the polar cap surface when the returning potential drop again exceeds the pair formation threshold. These charged particles would initiate the very next discharge (see Asseo & Melikidze [1998], Melikidze et al [2000], and GS00 for more detailed discussion). Therefore, the only net motion of sparks is the slow E < B drift across the planes of the surface magnetic field.…”

Section: Drifting Subpulse Phenomenonmentioning

confidence: 99%

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Formation of a Partially Screened Inner Acceleration Region in Radio Pulsars: Drifting Subpulses and Thermal X‐Ray Emission from Polar Cap Surface

Gil

Melikidze

Zhang

2006

ApJ

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The subpulse drifting phenomenon in pulsar radio emission is considered within the partially screened inner gap model, in which the sub-Goldreich-Julian thermionic flow of iron ions or electrons coexists with the spark-associated electron-positron plasma flow. We derive a simple formula that relates the thermal X-ray luminosity L X from the sparkheated polar cap and the E < B subpulse periodicityP 3 (polar cap carousel time). For PSRs B0943+10 and B1133+16, the only two pulsars for which bothP 3 and L X are known observationally, this formula holds well. For a few other pulsars, for which only one quantity is measured observationally, we predict the value of the other quantity and propose relevant observations that can confirm or discard the model. Then we further study the detailed physical conditions that allow such partially screened inner gap to form. By means of the condition T c /T s > 1 (where T c is the critical temperature above which the surface delivers a thermal flow to adequately supply the corotation charge density, and T s is the actual surface temperature), it is found that a partially screened gap (PSG) can be formed given that the near surface magnetic fields are very strong and curved. We consider both curvature radiation (CR) and resonant inverse Compton scattering (ICS) to produce seed photons for pair production, and find that the former is the main agency to produce gamma rays to discharge the PSG.

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Hydrodynamic analysis of electrostatic counter‐streaming instability in a spin‐polarized electron–positron–ion plasma

Khanum

Iqbal

Murtaza

2020

Contributions to Plasma Physics

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In this study, we present linear analysis of electrostatic counter-streaming instability in spin-polarized electron-positron-ion (e-p-i) plasma. With the aid of the separate spin evolution-quantum hydrodynamic (SSE-QHD) model, we derive the dispersion relation of counter-streaming instability. We numerically solve the dispersion and find four wave solutions: Langmuir wave, positron acoustic mode, and two electron and positron spin-dependent waves. It is noted that coupling of streaming and spin effects excites Langmuir instability and positron acoustic mode instability. However, in the absence of spin effect, only Langmuir instability will survive in e-p-i plasma. We have also discussed the effects of positron concentration, streaming speed, and spin polarization on the real frequency of waves and the growth rate. The present study may be helpful for understanding longitudinal wave propagation and instabilities in dense magnetized environments.

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Non-stationary pair plasma in a pulsar magnetosphere and the two-stream Instability

Cited by 110 publications

References 0 publications

Coupling between electrostatic and electromagnetic behaviour in a cylindrical equal-mass plasma

Coupling between electrostatic and electromagnetic behaviour in a cylindrical equal-mass plasma

Formation of a Partially Screened Inner Acceleration Region in Radio Pulsars: Drifting Subpulses and Thermal X‐Ray Emission from Polar Cap Surface

Hydrodynamic analysis of electrostatic counter‐streaming instability in a spin‐polarized electron–positron–ion plasma

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