Particle acceleration and radio emission above pulsar polar caps

1980 ◽  
Vol 235 ◽  
pp. 576 ◽  
Author(s):  
A. F. Cheng ◽  
M. A. Ruderman
Keyword(s):  
Particle Acceleration ◽  
Radio Emission ◽  
Polar Caps

scholarly journals Magnetospheric Structure of Rotation-Powered Neutron Stars

1992 ◽  
Vol 128 ◽  
pp. 56-77 ◽  
Author(s):  
Jonathan Arons
Keyword(s):  
Radio Emission ◽  
Gamma Radiation ◽  
Heavy Ions ◽  
Theoretical Work ◽  
Future Research ◽  
Observational Constraints ◽  
Polar Caps ◽  
Recent Theoretical Work ◽  
Density Flow ◽  
Promising Avenue

AbstractI survey recent theoretical work on the structure of the magnetospheres of rotation-powered pulsars, within the observational constraints set by their observed spindown, their ability to power synchrotron nebulae and their ability to produce beamed collective radio emission, while putting only a small fraction of their energy into incoherent X- and gamma radiation. I find no single theory has yet given a consistent description of the magnetosphere, but I conclude that models based on a dense outflow of pairs from the polar caps, permeated by a lower density flow of heavy ions, are the most promising avenue for future research.

Condensed Surfaces of Magnetic Neutron Stars and Particle Acceleration Above Pulsar Polar Caps

2008 ◽  
Author(s):  
Zach Medin ◽  
Dong Lai ◽  
C. Bassa ◽  
Z. Wang ◽  
A. Cumming ◽  
...  
Keyword(s):  
Particle Acceleration ◽  
Neutron Stars ◽  
Polar Caps

scholarly journals Magnetic annihilation in colliding-wind binary systems

1995 ◽  
Vol 163 ◽  
pp. 523-524
Author(s):  
M. Jardine ◽  
H.R. Allen ◽  
A.M.T. Pollock
Keyword(s):  
Particle Acceleration ◽  
Radio Emission ◽  
Magnetic Reconnection ◽  
Stagnation Point ◽  
Binary Systems ◽  
Nonthermal Radio ◽  
Nonthermal Radio Emission ◽  
Reconnection Model

We investigate the possibility that a stagnation-point magnetic reconnection model may account for the particle acceleration necessary for the generation of nonthermal radio emission in the Wolf-Rayet binary systems exemplified by WR140.

scholarly journals Hybrid numerical simulations of pulsar magnetospheres

2019 ◽  
Vol 491 (4) ◽  
pp. 5579-5585 ◽  
Author(s):  
Ioannis Contopoulos ◽  
Jerome Pétri ◽  
Petros Stefanou
Keyword(s):  
Particle Acceleration ◽  
Current Sheet ◽  
Electric Current ◽  
Hybrid Approach ◽  
High Energy ◽  
Basic Premise ◽  
Analytic Approximations ◽  
Polar Caps ◽  
Electron Positron ◽  
Field Lines

ABSTRACT We continue our investigation of particle acceleration in the pulsar equatorial current sheet (ECS). Our basic premise has been that the charge carriers in the current sheet originate in the polar caps as electron–positron pairs, and are carried along field lines that enter the ECS beyond the magnetospheric Y-point. In this work, we investigate further the charge replenishment of the ECS. We discovered that the flow of pairs from the rims of the polar caps cannot supply both the electric charge and the electric current of the ECS. The ECS must contain an extra amount of positronic (or electronic depending on orientation) electric current that originates in the stellar surface and flows outwards along the separatrices. We develop an iterative hybrid approach that self-consistently combines ideal force-free electrodynamics in the bulk of the magnetosphere with particle acceleration along the ECS. We derive analytic approximations for the orbits of the particles, and obtain the structure of the pulsar magnetosphere for various values of the pair formation multiplicity parameter κ. For realistic values κ ≫ 1, the magnetosphere is practically indistinguishable from the ideal force-free one, and therefore, the calculation of the spectrum of high energy radiation must rely on analytic approximations for the distribution of the accelerating electric field in the ECS.

scholarly journals The auroral radio emission of the magnetic B-type star ρ OphC

2020 ◽  
Vol 499 (1) ◽  
pp. L72-L76
Author(s):  
P Leto ◽  
C Trigilio ◽  
C S Buemi ◽  
F Leone ◽  
I Pillitteri ◽  
...  
Keyword(s):  
Radio Emission ◽  
Indirect Evidence ◽  
Magnetic Star ◽  
Early Type ◽  
Radiation Beam ◽  
Polar Caps ◽  
Thermal Radio ◽  
Thermal Radio Emission ◽  
Early Type Stars ◽  
Rotational Phase

ABSTRACT The non-thermal radio emission of main-sequence early-type stars is a signature of stellar magnetism. We present multiwavelength (1.6–16.7 GHz) ATCA measurements of the early-type magnetic star ρ OphC, which is a flat-spectrum non-thermal radio source. The ρ OphC radio emission is partially circularly polarized with a steep spectral dependence: the fraction of polarized emission is about $60{{\ \rm per\ cent}}$ at the lowest frequency sub-band (1.6 GHz) while is undetected at 16.7 GHz. This is clear evidence of coherent Auroral Radio Emission (ARE) from the ρ OphC magnetosphere. Interestingly, the detection of the ρ OphC’s ARE is not related to a peculiar rotational phase. This is a consequence of the stellar geometry, which makes the strongly anisotropic radiation beam of the amplified radiation always pointed towards Earth. The circular polarization sign evidences mainly amplification of the ordinary mode of the electromagnetic wave, consistent with a maser amplification occurring within dense regions. This is indirect evidence of the plasma evaporation from the polar caps, a phenomenon responsible for the thermal X-ray aurorae. ρ OphC is not the first early-type magnetic star showing the O-mode dominated ARE but is the first star with the ARE always on view.

scholarly journals On radio emission and related X-rays in solar-like stellar coronae

1996 ◽  
Vol 176 ◽  
pp. 485-492
Author(s):  
M. Güdel
Keyword(s):  
Particle Acceleration ◽  
Radio Emission ◽  
Coronal Heating ◽  
Emission Sources ◽  
X Rays ◽  
Direct Information ◽  
X Ray ◽  
Nonthermal Radio ◽  
Rotational Modulation ◽  
Magnetically Confined

Selected results relevant to coronal structuring in solar-like single stars based on combined radio and X-ray information are presented. Nonthermal radio and thermal soft X-ray emissions from coronal solar-like stars provide direct information on particle acceleration and coronal heating in the magnetically confined outer atmospheres. The structural relationship between the emission sources is mostly inferred from indirect arguments such as rotational modulation or gyroresonance emission. Direct VLBI provides evidence of resolved, extended coronae on solar-like stars.

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