The Natural Wave Modes in a Pulsar Magnetosphere

1977 ◽  
Vol 3 (2) ◽  
pp. 120-122 ◽  
Author(s):  
D. B. Melrose ◽  
R. J. Stoneham
Keyword(s):  
Radio Emission ◽  
Pulsar Magnetosphere ◽  
Natural Wave ◽  
Pulsar Radio ◽  
Electron Positron ◽  
Polarization Characteristics ◽  
Pulsar Radio Emission ◽  
Wave Modes

Our purpose in this paper is to explore the properties of the natural wave modes of a relativistically streaming electron-positron gas and to apply the results to the interpretation of the polarization characteristics of pulsar radio emission.

scholarly journals Propagation Effects on the Polarization of Pulsar Radio Emission

1979 ◽  
Vol 32 (2) ◽  
pp. 61 ◽  
Author(s):  
DB Melrose
Keyword(s):  
Radio Emission ◽  
Angular Separation ◽  
Pulsar Magnetosphere ◽  
Natural Wave ◽  
Strong Function ◽  
Pulsar Radio ◽  
Natural Modes ◽  
Low Density Limit ◽  
Pulsar Radio Emission ◽  
Polarized Radiation

The properties of the natural wave modes of a pulsar magnetosphere are derived in a simple way by appealing to the 'low-density limit'. The properties are evaluated explicitly for a general version of the cold plasma model which includes relativistic streaming motions, and it is argued that this model is probably adequate for pulsar magnetospheres. The observed circular polarization in pulsar radio emission could arise as a propagation effect; the conditions under which initially linear polarization could be converted into partially circularly polarized radiation are summarized. The observed 'orthogonal modes' of polarization could be due to components in the two natural modes having slightly different ray paths. The angular separation of the two rays is found to be a strong function of frequency (!!(), ~ 4 x 108 ne/ /2), and it is suggested that a study of the frequency dependence of 'orthogonal modes' could provide useful information.

scholarly journals Propagation Effects on Pulsar Radio Emission

2001 ◽  
Vol 18 (4) ◽  
pp. 400-406 ◽  
Author(s):  
Qinghuan Luo
Keyword(s):  
Radio Emission ◽  
Pulsar Magnetosphere ◽  
Pulsar Radio ◽  
Dispersion Effects ◽  
Electron Positron ◽  
Primary Particles ◽  
Propagation Effects ◽  
Plasma Dispersion ◽  
Pulsar Radio Emission ◽  
Relativistic Pair

AbstractPropagation effects on radio emission within the pulsar magnetosphere are discussed. Widely accepted pulsar models assume that a pulsar magnetosphere is populated with relativistic pair plasmas produced through electron–positron cascades by accelerated primary particles above the polar cap. Any radio emission produced well inside the light cylinder (the radius at which the rotation speed equals c) must propagate through the magnetospheric plasma and be subject to plasma dispersion effects such as refraction and absorption. The observed pulse profiles should contain some features that reflect the influence of the intervening plasma. I discuss particularly the absorption effect due to cyclotron resonance and its possible observational consequences.

scholarly journals Alfvén resonance absorption in electron-positron plasmas

2010 ◽  
Vol 6 (S274) ◽  
pp. 224-227 ◽  
Author(s):  
N. F. Cramer
Keyword(s):  
Mode Conversion ◽  
Alfven Wave ◽  
Pulsar Magnetosphere ◽  
Pulsar Radio ◽  
Inertial Alfvén Wave ◽  
Pair Plasma ◽  
Electron Positron ◽  
Normal Electron ◽  
The Magnetic Field ◽  
Pulsar Radio Emission

AbstractWaves propagating obliquely in a magnetized cold pair plasma experience an approximate resonance in the wavevector component perpendicular to the magnetic field, which is the analogue of the Alfvén resonance in normal electron-ion plasmas. Wave absorption at the resonance can take place via mode conversion to the analogue of the short wavelength inertial Alfvén wave. The Alfvén resonance could play a role in wave propagation in the pulsar magnetosphere leading to pulsar radio emission. Ducting of waves in strong plasma gradients may occur in the pulsar magnetosphere, which leads to the consideration of Alfvén surface waves, whose energy is concentrated in the region of strong gradients.

scholarly journals Coherent Mechanisms of Pulsar Radio Emission

2000 ◽  
Vol 177 ◽  
pp. 389-392
Author(s):  
Maxim Lyutikov ◽  
Roger Blandford ◽  
George Machabeli
Keyword(s):  
Radio Emission ◽  
Normal Modes ◽  
Relativistic Plasma ◽  
Primary Beam ◽  
Dimensional Electron ◽  
Pulsar Radio ◽  
One Dimensional ◽  
Electron Positron ◽  
Pulsar Radio Emission

AbstractRelativistic plasma masers operating on the anomalous cyclotron-Cherenkov resonanceω−k||υ||+ωB/ϒres= 0 and the Cherenkov-drift resonanceω−k||υ||−kx/ud= 0, are capable of explaining the main observational characteristics of pulsar radio emission. Both electromagnetic instabilities are due to the interaction of the fast particles from the primary beam and from the tail of the secondary pairs distribution with the normal modes of a strongly magnetized one-dimensional electron-positron plasma. In a typical pulsar both resonances occur in the outer parts of magnetosphere atrres≈ 109cm.

scholarly journals Single Pulses and the Plasma-physical Processes of Pulsar Radio Emission

2017 ◽  
Vol 13 (S337) ◽  
pp. 73-78
Author(s):  
Joanna M. Rankin
Keyword(s):  
Radio Emission ◽  
Pulse Sequences ◽  
Single Pulse ◽  
Physical Processes ◽  
Pulsar Emission ◽  
Pulsar Radio ◽  
Cone Model ◽  
Chart Recorder ◽  
Polarization Characteristics ◽  
Pulsar Radio Emission

AbstractPulsars were discovered on the basis of their individual pulses, first by Jocelyn Bell and then by many others. This was chart-recorder science as computers were not yet in routine use. Single pulses carry direct information about the emission process as revealed in the detailed properties of their polarization characteristics. Early analyses of single pulses proved so dizzyingly complex that attention shifted to study of average profiles. This is turn led to models of pulsar emission beams—in particular the core/double-cone model—which now provides a foundation for understanding single-pulse sequences. We mention some of the 21stC single-pulse surveys and conclude with a brief discussion of our own recent analyses leading to the identification of the pulsar radio-emission mechanism of both slow and millsecond pulsars.

scholarly journals A Resonant-Mode Model of Pulsar Radio Emission

2004 ◽  
Vol 218 ◽  
pp. 365-368 ◽  
Author(s):  
M. D. T. Young
Keyword(s):  
Radio Emission ◽  
Resonant Cavity ◽  
Resonant Mode ◽  
Beam Current ◽  
Frequency Range ◽  
Pulsar Magnetosphere ◽  
Pulsar Radio ◽  
Polar Gap ◽  
Waveguide System ◽  
Pulsar Radio Emission

It is argued that the polar gap and flux tube in the pulsar magnetosphere act as a resonant cavity/waveguide system which is excited by oscillations in the primary beam current and accelerating potential. The modes will be converted, probably scattered, to produce radio beams in the frequency range of those observed.

scholarly journals Exploiting simultaneous multi-frequency observations to probe polar-cap processes

2017 ◽  
Vol 13 (S337) ◽  
pp. 366-367
Author(s):  
Yogesh Maan
Keyword(s):  
Radio Emission ◽  
Wide Band ◽  
Magnetic Axis ◽  
Pulsar Magnetosphere ◽  
Polar Cap ◽  
Pulsar Radio ◽  
Magnetic Latitude ◽  
Physical Quantities ◽  
Pulsar Radio Emission ◽  
Different Altitudes

AbstractSub-pulse drifting has been regarded as one of the most insightful aspects of the pulsar radio emission. The phenomenon is generally explained with a system of emission sub-beams rotating around the magnetic axis, originating from a carousel of sparks near the pulsar surface (the carousel model). Since the observed radio emission at different frequencies is generated at different altitudes in the pulsar magnetosphere, corresponding sampling of the carousel on the polar cap differs slightly in magnetic latitude. When this aspect is considered, it is shown here that the carousel model predicts important observable effects in multi-frequency or wide-band observations. Also presented here are brief mentions of how this aspect can be exploited to probe the electrodynamics in the polar cap by estimating various physical quantities, and correctly interpret various carousel related phenomena, in addition to test the carousel model itself.

scholarly journals Plasma Masers in Radio Pulsars

2000 ◽  
Vol 195 ◽  
pp. 243-244
Author(s):  
M. Lyutikov ◽  
R. Blandford ◽  
G. Machabeli
Keyword(s):  
Radio Emission ◽  
Normal Modes ◽  
Relativistic Plasma ◽  
Primary Beam ◽  
Dimensional Electron ◽  
Radio Pulsars ◽  
Pulsar Radio ◽  
One Dimensional ◽  
Electron Positron ◽  
Pulsar Radio Emission

Relativistic plasma masers operating on the anomalous cyclotron-Cherenkov resonance (ω - k||v|| + ωB/γres = 0) and on the Cherenkovdrift resonance (ω - k||v|| - kxud = 0) are capable of explaining the main observational characteristics of pulsar radio emission. Both electromagnetic instabilities are due to the interaction of the fast particles of the primary beam and from the tail of the distribution with the normal modes of a strongly magnetized, one-dimensional electron-positron plasma. In a typical pulsar, both resonances occur in the outer parts of the magnetosphere at rres ≍ 109 cm.

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 Parameters of microstructure and noiselike intensity fluctuation in pulsar radio emission measured with submicrosecond time resolution provided by the S2 VLBI recording/playback system

2000 ◽  
Vol 177 ◽  
pp. 179-180 ◽  
Author(s):  
M.V. Popov ◽  
V.I. Kondrat’ev ◽  
V.I. Altunin ◽  
N. Bartel ◽  
W. Cannon ◽  
...  
Keyword(s):  
Radio Emission ◽  
Data Acquisition ◽  
Radio Telescope ◽  
Time Resolution ◽  
Intensity Fluctuation ◽  
Data Acquisition System ◽  
Acquisition System ◽  
Pulsar Radio ◽  
Removal Technique ◽  
Pulsar Radio Emission

AbstractThree bright pulsars (B0950+08, B1133+16, and B1929+10) were observed with the 70-m radio telescope in Tidbinbilla at a frequency of 1650 MHz using the S2 Data Acquisition System which provided continuous recording of pulsar signals in two conjugate bands of B=16 MHz each. Parameters of microstructure have been analyzed using the predetection dispersion removal technique.

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