scholarly journals Polarization in Pulsar Radio Emission

1992 ◽  
Vol 128 ◽  
pp. 384-386
Author(s):  
D. M. GOULD
Keyword(s):  
Radio Emission ◽  
Circular Polarization ◽  
Linear Polarization ◽  
Large Data ◽  
Position Angle ◽  
Published Data ◽  
Data Set ◽  
Pulsar Radio ◽  
Polarization Profiles ◽  
Pulsar Radio Emission

Polarimetric observations of over 300 pulsars have been carried out between 21 December 1988 and 22 January 1990 at 606, 610, 925, and 1408 MHz using the Lovell Telescope at Jodrell Bank. Many of these pulsars have no previously published polarization profiles and will be published shortly (Gould and Lyne 1990). This large data set along with previously published data from various sources, has been used to test the correlation found by Radhakrishnan and Rankin (1990) between sense reversing circular polarization signatures and the accompanying sense of rotation of the linear polarization position angle.

scholarly journals Characteristics of Pulsar Radio Emission at Single-pulse Resolution

2000 ◽  
Vol 177 ◽  
pp. 149-154
Author(s):  
Avinash A. Deshpande
Keyword(s):  
Radio Emission ◽  
Weighted Average ◽  
Single Pulse ◽  
Position Angle ◽  
Complex Nature ◽  
Stable States ◽  
Pulsar Radio ◽  
Emission Profile ◽  
Secondary State ◽  
Pulsar Radio Emission

Pulsar radio emission shows remarkably rich, but complex behavior in both intensity and polarization when considered on a pulse-to-pulse basis. A large number of pulses, when averaged together, tend to approach & define stable shapes that can be considered as distinct signatures of different pulsars. Such average profiles have shapes ranging from that describable as a simple one-component profile to those suggesting as many as 9 components. The components are understood as resulting from an average of many, often narrower, intities — the subpulses —that appear within the longitude range of a given component. The pulse components are thusformedand represent statistically an intensity-weighted average pattern of the radiation received as a function of longitude. The profile mode changes recognized in many pulsars suggest that the emission profile of a given pulsar may have two quasi-stable states, with one (primary) state more probable/brighter than the other (secondary) state. There are also (often associated) polarization modes that represent polarization states that are orthogonal to each other. The complex nature of orthogonaljumpsobserved in polarization position-angle sweeps may be attributable to possible superposition of two profile/polarization modes with orthogonal polarizations.

scholarly journals Evolution of Multipolar Magnetic Fields in Isolated Neutron Stars and its effect on Pulsar Radio Emission

2000 ◽  
Vol 177 ◽  
pp. 265-266
Author(s):  
D. Mitra ◽  
S. Konar ◽  
D. Bhattacharya ◽  
A. V. Hoensbroech ◽  
J. H. Seiradakis ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Radio Emission ◽  
Neutron Stars ◽  
Pulse Shape ◽  
Position Angle ◽  
Emission Region ◽  
Pulsar Radio ◽  
Significant Frequency ◽  
The Magnetic Field ◽  
Pulsar Radio Emission

AbstractThe evolution of the multipolar structure of the magnetic field of isolated neutron stars is studied assuming the currents to be confined to the crust. Lower orders (≤ 25) of multipole are seen to evolve in a manner similar to the dipole suggesting little or no evolution of the expected pulse shape. We also study the multifrequency polarization position angle traverse of PSR B0329+54 and find a significant frequency dependence above 2.7 GHz. We interpret this as an evidence of strong multipolar magnetic field present in the radio emission region.

scholarly journals On the Nature of the Circularly Polarized Component of Pulsar Radio Emission

1992 ◽  
Vol 128 ◽  
pp. 375-377 ◽  
Author(s):  
Ya. N. Istomin
Keyword(s):  
Radio Emission ◽  
Circular Polarization ◽  
Polar Cap ◽  
Core Component ◽  
Pulsar Radio ◽  
Left Hand ◽  
Polarized Waves ◽  
The Magnetic Field ◽  
Group Velocities ◽  
Pulsar Radio Emission

AbstractIt is shown that circular polarization occurs in the region of cyclotron resonance because the group velocities of right-hand and left-hand polarized waves are different with respect to the direction of the magnetic field. Due to the dependence of the intensity of radio emission on the coordinates across the polar cap, this difference in group velocities leads to noncompensated circular polarization proportional to the derivative of the total intensity as a function of longitude. The indicated dependence corresponds to observations of the so-called core component of pulsar radio emission.

scholarly journals Orthogonal Polarization Modes in Pulsar Radio Emission

2004 ◽  
Vol 218 ◽  
pp. 377-380
Author(s):  
S. A. Petrova
Keyword(s):  
Radio Emission ◽  
Field Line ◽  
Plasma Density ◽  
Orthogonal Polarization ◽  
Pulsar Radio ◽  
Open Field Line ◽  
Exponential Decrease ◽  
Polarization Profiles ◽  
First Time ◽  
Pulsar Radio Emission

General features of polarization transfer in the plasma of pulsar magnetospheres are outlined. A technique of plasma density diagnostics based on observed polarization profiles of radio pulses is developed. For the first time, it appears possible to obtain the profiles of the plasma density across the open field line tube from observations. The multiplicities derived are compatible with those predicted by modern theories of pair cascade and show a perfect exponential decrease towards the tube edge. Implications of the results are briefly discussed.

scholarly journals Orthogonal Mode Polarization of Pulsar Radio Emission

2004 ◽  
Vol 218 ◽  
pp. 381-382
Author(s):  
Q. Luo ◽  
D. B. Melrose
Keyword(s):  
Numerical Simulation ◽  
Radio Emission ◽  
Circular Polarization ◽  
Single Pulse ◽  
Pulsar Radio ◽  
Natural Modes ◽  
Elliptically Polarized ◽  
Pulsar Radio Emission

We discuss a model for polarization of pulsar radio emission, based on the assumption that waves propagate in two elliptically polarized natural modes. Some results from numerical simulation of single pulses are discussed with emphasis on circular polarization, microstructures and single pulse statistics.

scholarly journals DETERMINATION OF THE ROTATION MEASURE VALUE SIGN WHEN RECEIVING A SINGLE LINEAR POLARIZATION OF THE PULSAR RADIO EMISSION

2020 ◽  
Vol 25 (4) ◽  
pp. 253-267
Author(s):  
O. M. Ulyanov ◽  
◽  
A. I. Shevtsova ◽  
S. M. Yerin ◽  
◽  
...  
Keyword(s):  
Magnetic Field ◽  
Radio Emission ◽  
Linear Polarization ◽  
Pulsar Radio ◽  
Absolute Value ◽  
The Earth ◽  
Rotation Measure ◽  
The Absolute ◽  
Pulsar Radio Emission

Purpose: The studies of pulsars allow enriching our knowledge in determination of parameters of both the exotic electron-positron plasma in the pulsar magnetosphere with strong magnetic field and the ordinary ion-electron plasma of the interstellar medium, which exists in a weak magnetic field. To determine the parameters of the both plasma types it is reasonable to use polarization characteristics of a pulsed radio emission of pulsars. An accurate determination of these characteristics is quite a complex problem. For its solving, primarily we have to determine two parameters of the propagation medium – its dispersion and rotation measures. Their absolute values can be determined with the relative precision of 10-4, but the problem of rotation measure value sign determination arises. This sign depends on the interstellar magnetic field direction along the line of sight. Hear, a new method of rotation measure value sign determination is proposed. Design/methodology/approach: Muller polarization matrices are usually used for determination of such a propagation parameter as the rotation measure absolute value. When only one linear polarization is received, using of these matrices allows quite accurate determining the absolute value of the rotation measure, but not the sign of this parameter due to a certain symmetry of these matrices with respect to the direction of the linear polarization rotation plane. If we complement the system of equations, which determines the rotation measure value, with some new additional components, which take into account the contributions of the Earth ionosphere and magnetosphere to the rotation measure value, one can notice that this contribution is always positive in the Southern magnetic hemisphere (the majority of the Northern geographical hemisphere) and is always negative in the Northern magnetic hemisphere (the majority of the Southern geographical hemisphere). Moreover, the absolute value of this contribution is maximal at noon and minimal at midnight, when the concentration of ions in the Earth ionosphere is maximal and minimal, respectively. Accounting for these regularities allows to determine not only the absolute value of the rotation measure, but also its sign by means of two independent time-shifted estimations of the observed absolute value of this parameter for various ionization degrees of the Earth ionosphere. Findings: We show that using of additional equations, which take into account the contribution of the Earth ionosphere and magnetosphere to the value of the rotation measure parameter, allows full determination of this parameter accounting for the sign of this value even for the antennas, which can record a single linear polarization only. This approach allows to determine all polarization parameters of the pulsar radio emission as well as of the pulsed or continuum polarized radio emission of other cosmic sources. Conclusions: The paper presents the results of measurement of the rotation measure for the two closest to the Earth pulsars, namely J0814+7429 (B0809+74), J0953+0755 (B0950+08), and the comparison of the proposed technique for this parameter determination with other existing techniques. Key words: pulse, dispersion measure, rotation measure, plasma, polarization, pulsar, radio telescope

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