scholarly journals Dissipation in Poynting‐Flux–dominated Flows: The σ‐Problem of the Crab Pulsar Wind

2003 ◽  
Vol 591 (1) ◽  
pp. 366-379 ◽  
Author(s):  
J. G. Kirk ◽  
O. Skjaraasen
Keyword(s):  
Crab Pulsar ◽  
Poynting Flux ◽  
Pulsar Wind

scholarly journals The σ Problem of the Crab Pulsar Wind

2004 ◽  
Vol 218 ◽  
pp. 171-174
Author(s):  
J. G. Kirk ◽  
O. Skjæraasen
Keyword(s):  
Dissipation Rate ◽  
A Priori ◽  
Termination Shock ◽  
Crab Pulsar ◽  
Complete Conversion ◽  
Poynting Flux ◽  
Dissipation Rates ◽  
Pulsar Wind

The conversion of the Crab pulsar wind from one dominated by Poynting flux close to the star to one dominated by particle-borne energy at the termination shock is considered. The idea put forth by Coroniti (1990) and criticized by Lyubarsky & Kirk (2001) that reconnection in a striped wind is responsible, is generalized to include faster prescriptions for the a priori unknown dissipation rate. Strong acceleration of the wind is confirmed, and the higher dissipation rates imply complete conversion of Poynting flux into particle-borne flux within the unshocked wind.

scholarly journals Near‐Infrared, Kilosecond Variability of the Wisps and Jet in the Crab Pulsar Wind Nebula

2005 ◽  
Vol 633 (2) ◽  
pp. 931-940 ◽  
Author(s):  
A. Melatos ◽  
D. Scheltus ◽  
M. T. Whiting ◽  
S. S. Eikenberry ◽  
R. W. Romani ◽  
...  
Keyword(s):  
Near Infrared ◽  
Crab Pulsar ◽  
Pulsar Wind

scholarly journals A corrugated termination shock in pulsar wind nebulae?

2016 ◽  
Vol 82 (4) ◽  
Author(s):  
Martin Lemoine
Keyword(s):  
Magnetic Field ◽  
Crab Nebula ◽  
Radiation Reaction ◽  
Termination Shock ◽  
Pulsar Wind Nebulae ◽  
Order Unity ◽  
Poynting Flux ◽  
Electron Positron ◽  
Pulsar Wind ◽  
The Crab Nebula

Successful phenomenological models of pulsar wind nebulae assume efficient dissipation of the Poynting flux of the magnetized electron–positron wind as well as efficient acceleration of the pairs in the vicinity of the termination shock, but how this is realized is not yet well understood. This paper suggests that the corrugation of the termination shock, at the onset of nonlinearity, may lead towards the desired phenomenology. Nonlinear corrugation of the termination shock would convert a fraction of order unity of the incoming ordered magnetic field into downstream turbulence, slowing down the flow to sub-relativistic velocities. The dissipation of turbulence would further preheat the pair population on short length scales, close to equipartition with the magnetic field, thereby reducing the initial high magnetization to values of order unity. Furthermore, it is speculated that the turbulence generated by the corrugation pattern may sustain a relativistic Fermi process, accelerating particles close to the radiation reaction limit, as observed in the Crab nebula. The required corrugation could be induced by the fast magnetosonic modes of downstream nebular turbulence; but it could also be produced by upstream turbulence, either carried by the wind or seeded in the precursor by the accelerated particles themselves.

scholarly journals Theory of Pulsar Winds

2004 ◽  
Vol 218 ◽  
pp. 143-150
Author(s):  
A. Melatos
Keyword(s):  
Linear Accelerator ◽  
Recent Progress ◽  
Near Infrared ◽  
Poynting Flux ◽  
Open Questions ◽  
Field Geometry ◽  
Parametric Instabilities ◽  
Pulsar Wind ◽  
Pulsar Winds ◽  
The Magnetic Field

Recent progress in the theory of pulsar wind electrodynamics is reviewed, with emphasis on the following open questions, (i) Is the bipolar, jet-torus geometry imprinted by collimation or injection? (ii) what is the magnetic field geometry as a function of latitude, and is it stable? (iii) How rapidly does the postshock flow fluctuate, e.g. in the near infrared? (iv) The σ paradox: is Poynting flux converted gradually to kinetic energy flux as the wind expands, as in a linear accelerator, or is the conversion lossy, due to reconnection or parametric instabilities in a wave-like outflow?

scholarly journals Energy Transport in a Rotation-Modulated Pulsar Wind

1996 ◽  
Vol 160 ◽  
pp. 421-424 ◽  
Author(s):  
A. Melatos ◽  
D. B. Melrose
Keyword(s):  
Energy Transport ◽  
Wave Model ◽  
Termination Shock ◽  
Displacement Current ◽  
Nonlinear Plasma ◽  
Poynting Flux ◽  
Self Consistent ◽  
Radiation Zone ◽  
Pulsar Wind ◽  
Nonlinear Plasma Wave

AbstractThe structure and energetics of a rotation-modulated pulsar wind are examined. It is shown that the displacement current in the wind asymptotically dominates the conduction current, creating an outer radiation zone whose inner boundary lies well inside the wind termination shock. A self-consistent nonlinear-plasma-wave model of the radiation zone predicts that the ratio of Poynting flux to kinetic-energy flux at the termination shock is small (~ 10−3for the Crab), in agreement with independent observational estimates.

scholarly journals The Crab pulsar and its pulsar-wind nebula in the optical and infrared

2009 ◽  
Vol 508 (1) ◽  
pp. 221-228 ◽  
Author(s):  
A. Tziamtzis ◽  
P. Lundqvist ◽  
A. A. Djupvik
Keyword(s):  
Crab Pulsar ◽  
Pulsar Wind

Magnetohydrodynamic Acceleration of the Crab Pulsar Wind

2002 ◽  
Vol 573 (1) ◽  
pp. L31-L34 ◽  
Author(s):  
I. Okamoto
Keyword(s):  
Crab Pulsar ◽  
Pulsar Wind

scholarly journals Ultra-high-energy Gamma-Ray Radiation from the Crab Pulsar Wind Nebula

2022 ◽  
Vol 924 (2) ◽  
pp. 42
Author(s):  
Lin Nie ◽  
Yang Liu ◽  
Zejun Jiang ◽  
Xiongfei Geng
Keyword(s):  
Gamma Ray ◽  
Crab Nebula ◽  
High Energy ◽  
Model Parameters ◽  
Wave Band ◽  
Crab Pulsar ◽  
High Energy Gamma ◽  
Energy Gamma ◽  
Pulsar Wind ◽  
The Crab Nebula

Abstract It has been long debated whether the high-energy gamma-ray radiation from the Crab Nebula stems from leptonic or hadronic processes. In this work, we investigate the multiband nonthermal radiation from the Crab pulsar wind nebula with the leptonic and leptonic–hadronic hybrid models, respectively. Then we use the Markov Chain Monte Carlo sampling technology and method of sampling trace to study the stability and reasonability of the model parameters according to the recently observed results and obtain the best-fitting values of parameters. Finally, we calculate different radiative components generated by the electrons and protons in the Crab Nebula. The modeling results indicate that the pure leptonic origin model with the one-zone only can partly agree with some segments of the data from various experiments (including the PeV gamma-ray emission reported by the LHAASO and the other radiation ranging from the radio to very-high-energy gamma-ray wave band), and the contribution of hadronic interaction is hardly constrained. However, we find that the hadronic process may also contribute, especially in the energy range exceeding the PeV. In addition, it can be inferred that the higher energy signals from the Crab Nebula could be observed in the future.

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