scholarly journals A rotation-driven pulsar radio emission mechanism

2020 ◽  
Vol 500 (4) ◽  
pp. 4549-4559
Author(s):  
D B Melrose ◽  
M Z Rafat ◽  
A Mastrano
Keyword(s):  
Radio Emission ◽  
Rest Frame ◽  
Radial Distance ◽  
Lorentz Factor ◽  
Emission Mechanism ◽  
Pulsar Radio ◽  
Specific Frequency ◽  
The Mean ◽  
Pulsar Radio Emission ◽  
Streaming Motion

ABSTRACT We propose and discuss an alternative pulsar radio emission mechanism that relies on rotation-driven plasma oscillations, rather than on a beam-driven instability, and suggest that it may be the generic radio emission mechanism for pulsars. We identify these oscillations as superluminal longitudinal waves in the pulsar plasma and point out that these waves can escape directly in the O mode. We argue that the frequency of the oscillations is ω0 ≈ ωp(2〈γ〉)1/2/γs, where γs is the Lorentz factor of bulk streaming motion and 〈γ〉 is the mean Lorentz factor in the rest frame of the plasma. The dependence of the plasma frequency ωp on radial distance implies a specific frequency-to-radius mapping, ω0∝r−3/2. Escape of the energy in these oscillations is possible if they are generated in overdense, field-aligned regions that we call fibres; the wave energy is initially refracted into underdense regions between the fibres, which act as ducts. Some implications of the model for the interpretation of pulsar radio emission are discussed.

scholarly journals Pulsar radio emission mechanisms: a critique

2020 ◽  
Vol 500 (4) ◽  
pp. 4530-4548
Author(s):  
D B Melrose ◽  
M Z Rafat ◽  
A Mastrano
Keyword(s):  
Radio Emission ◽  
Gaussian Distribution ◽  
Rest Frame ◽  
Particle Distribution ◽  
Lorentz Factor ◽  
Relativistic Case ◽  
Pulsar Radio ◽  
Kinetic Instability ◽  
Wave Properties ◽  
Pulsar Radio Emission

ABSTRACT We consider critically the three most widely favoured pulsar radio emission mechanisms: coherent curvature emission (CCE), beam-driven relativistic plasma emission (RPE), and anomalous Doppler emission (ADE). We assume that the pulsar plasma is 1D, streaming outwards with a bulk Lorentz factor γs ≫ 〈γ〉 − 1 ≳ 1, where 〈γ〉 is the intrinsic spread in the rest frame of the plasma. We argue that the formation of beams in a multicloud model is ineffective in the intrinsically relativistic case for plausible parameters because the overtaking takes too long. We argue that the default choice for the particle distribution in the rest frame is a Jüttner distribution and that relativistic streaming should be included by applying a Lorentz transformation to the rest-frame distribution, rather than the widely assumed relativistically streaming Gaussian distribution. We find that beam-driven wave growth is severely restricted by (a) the wave properties in pulsar plasma, (b) a separation condition between beam and background, and (c) the inhomogeneity of the plasma in the pulsar frame. The growth rate for the kinetic instability is much smaller and the bandwidth of the growing waves is much larger for a Jüttner distribution than for a relativistically streaming Gaussian distribution. No reactive instability occurs at all for a Jüttner distribution. We conclude that none of CCE, RPE, and ADE is tenable as the generic pulsar radio emission mechanism for ‘plausible’ assumptions about the pulsar plasma.

scholarly journals Microstructure and the Pulsar Radio Emission Mechanism

1992 ◽  
Vol 128 ◽  
pp. 343-346
Author(s):  
Valentín Boriakoff
Keyword(s):  
Radio Emission ◽  
Radio Pulse ◽  
Emission Mechanism ◽  
Pulsar Radio ◽  
Pulsar Radio Emission

AbstractThe properties of pulsar radio pulse microstructure are reviewed, then consideration is given on how, in the frame of the Ruderman-Sutherland pulsar model, an emission mechanism can be devised which explains many of the known characteristics of micropulses and of subpulses.

scholarly journals Computer Simulation of Electron-Flow Bunching in the Pulsar Magnetosphere

1992 ◽  
Vol 128 ◽  
pp. 319-321
Author(s):  
Yu. A. Rylov
Keyword(s):  
Radio Emission ◽  
Electron Bunch ◽  
Electron Flow ◽  
Emission Mechanism ◽  
Pulsar Radio ◽  
Electron Bunches ◽  
Thermal Radio Emission ◽  
Gas Heating ◽  
Outflow Channel ◽  
Pulsar Radio Emission

Bunch curvature emission is one of the well known pulsar radio emission mechanisms. The problem of bunch formation is very important for understanding the pulsar radio emission mechanism. In the axisymmetric pulsar magnetospheric bunching arises in the outflow channel as a result of interaction between moving electrons (DP) and captured ones (SP) (Rylov 1988). A numerical simulation was undertaken to determine how strongly the electron flow is bunched. The bunching appears to be very strong. It can be treated as a gas of electron bunches rather than small fluctuations of the electron flow. The thermal radio emission of the electron-bunch gas has a very high brightness temperature and sharp directivity. The power consumed in electron-bunch gas heating is sufficient to explain the pulsar radio emission. The pulsar radio emission mechanism appears to be thermal (the electron bunches move chaotically) and coherent (electrons of the bunch emit coherently) at the same time. For this reason the radio emission mechanism is very stable.

Pulsar Radio Emission Mechanism

1973 ◽  
Vol 182 ◽  
pp. 935 ◽  
Author(s):  
Virtamo Jorma ◽  
Pekka Jauho
Keyword(s):  
Radio Emission ◽  
Emission Mechanism ◽  
Pulsar Radio ◽  
Pulsar Radio Emission

scholarly journals Maser Theory of Pulsar Radiation

1971 ◽  
Vol 46 ◽  
pp. 414-428
Author(s):  
Hong-Yee Chiu
Keyword(s):  
Radio Emission ◽  
Plasma Emission ◽  
Emission Mechanism ◽  
Radio Flux ◽  
High Brightness ◽  
Pulsar Radio ◽  
Pulsar Radiation ◽  
Amplification Process ◽  
Coherent Plasma ◽  
Pulsar Radio Emission

In this paper we present an account of a theory of pulsar radio emission. The emission mechanism is via a maser amplification process. This theory avoids the difficulty of coherent plasma emission, that the bandwidth of radiation must be less than 1/2 λ. The high brightness radio temperature and the insensitivity of pulsar radio flux to pulsar periods can be easily accounted for.

scholarly journals Pulsar Radio Emission Mechanism: Radio Nanoshots as a Low-frequency Afterglow of Relativistic Magnetic Reconnection

2019 ◽  
Vol 876 (1) ◽  
pp. L6 ◽  
Author(s):  
Alexander Philippov ◽  
Dmitri A. Uzdensky ◽  
Anatoly Spitkovsky ◽  
Benoît Cerutti
Keyword(s):  
Radio Emission ◽  
Magnetic Reconnection ◽  
Low Frequency ◽  
Emission Mechanism ◽  
Pulsar Radio ◽  
Pulsar Radio Emission
Sign in / Sign up

Export Citation Format

Share Document