scholarly journals Propagation of Electromagnetic Waves in Pulsar Magnetospheres

2001 ◽  
Vol 182 ◽  
pp. 77-80
Author(s):  
Ya. Istomin
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Waves ◽  
Numerical Code ◽  
Pulsar Magnetosphere ◽  
Electron Positron ◽  
The Waves

AbstractWe have developed a numerical code for the propagation of different electromagnetic modes in a pulsar magnetosphere filled by a relativistic, streaming electron-positron plasma in a strong, curved magnetic field. We determine the trajectories, limiting polarization and damping of the waves leaving the magnetosphere.

scholarly journals Radio Emission Model of a 'Typical' Pulsar

1987 ◽  
Vol 40 (6) ◽  
pp. 755 ◽  
Author(s):  
AZ Kazbegi ◽  
GZ Machabeli ◽  
G Melikidze
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Waves ◽  
Emission Model ◽  
Radio Waves ◽  
Resonance Case ◽  
Pulsar Magnetosphere ◽  
Pulsar Emission ◽  
Dipole Magnetic Field ◽  
New Type ◽  
The Magnetic Field

The generation of radio waves in the plasma of the pulsar magnetosphere is considered taking into account the inhomogeneity of the dipole magnetic field. It is shown that the growth rate of the instability of the electromagnetic waves calculated in the non-resonance case turns out to be of the order of 1/ TO (where TO is the time of plasma escape from the light cylinder). However, the generation of electromagnetic waves from a new type Cherenkov resonance is possible, occurring when the particles have transverse velocities caused by the drift due to the inhomogeneity of the magnetic field. Estimates show that the development of this type of instability is possible only for pulsars with ages which exceed 104 yr. We make an attempt to explain some peculiarities of 'typical' pulsar emission on the basis of the model developed.

scholarly journals Time-variability of the Crab Nebula wisps

2000 ◽  
Vol 177 ◽  
pp. 507-508 ◽  
Author(s):  
Anatoly Spitkovsky ◽  
Jonathan Arons
Keyword(s):  
Magnetic Field ◽  
Crab Nebula ◽  
Propagation Speed ◽  
Time Dependent ◽  
Time Variability ◽  
Electron Positron ◽  
Pair Density ◽  
Pulsar Wind ◽  
The Crab Nebula ◽  
The Waves

AbstractWe present results of time-dependent numerical modeling of the internal structure of the collisionless shock terminating the pulsar wind in Crab Nebula. We treat the equatorial relativistic wind as composed of ions and electron-positron plasma with an embedded toroidal magnetic field. Relativistic cyclotron instability of the ion ring downstream from the shock is found to launch outward propagating magnetosonic waves. Due to the fresh supply of ions crossing the shock, the time-dependent process achieves a limit-cycle pattern, in which the waves are launched with periodicity on the order of the ion Larmor time. Compressions in magnetic field and pair density associated with these waves as well as their propagation speed qualitatively reproduce the features observed in the wisps.

Propagation of electromagnetic waves in a warm plasma-filled cylindrical waveguide in the presence of an external magnetic field

1983 ◽  
Vol 29 (3) ◽  
pp. 383-392 ◽  
Author(s):  
Sanjay Kumar Ghosh ◽  
S. P. Pal
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Electromagnetic Waves ◽  
Transverse Magnetic ◽  
Cylindrical Waveguide ◽  
Small Magnetic Field ◽  
Warm Plasma ◽  
Plasma Theory ◽  
The Waves ◽  
Constant External Magnetic Field

The propagation of electromagnetic waves in a plasma-filled cylindrical waveguide in the presence of a constant external magnetic field is investigated using warm plasma theory. It is found that the waves cannot be separated into transverse magnetic and transverse electric modes; only hybrid modes are propagated. Dispersion relations are derived for zero, finite and infinite magnetic fields. Frequency shifts for the wave propagation in the case of a small magnetic field are calculated.

scholarly journals Whistler waves observed by Solar Orbiter during its first orbit

2021 ◽  
Author(s):  
Matthieu Kretschmar ◽  
Thomas Chust ◽  
Daniel Graham ◽  
Volodya Krasnosekskikh ◽  
Lucas Colomban ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Electromagnetic Waves ◽  
Heliocentric Distance ◽  
Plasma Waves ◽  
Distribution Functions ◽  
The Sun ◽  
Whistler Waves ◽  
Velocity Distribution Functions ◽  
The Waves

<p>Plasma waves can play an important role in the evolution of the solar wind and the particle velocity distribution functions in particular. We analyzed the electromagnetic waves observed above a few Hz by the Radio Plasma Waves (RPW) instrument suite onboard Solar Orbiter, during its first orbit, which covered a distance from the Sun between 1 AU and 0.5 AU.  We identified the majority of the detected waves as whistler waves with frequency around  0.1 f_ce and right handed circular polarisation. We found these waves to be mostly aligned or anti aligned with the ambient magnetic field, and rarely oblique. We also present and discuss their direction of propagation and the variation of the waves' properties with heliocentric distance.</p>

scholarly journals Some Peculiaritiers of the Relativistic Electron-Positron Plasma Dynamics in the Pulsar Magnetosphere

2000 ◽  
Vol 177 ◽  
pp. 465-468
Author(s):  
Irakli S. Nanobashvili
Keyword(s):  
Magnetic Field ◽  
Relativistic Electron ◽  
Centrifugal Force ◽  
Plasma Particle ◽  
Pulsar Magnetosphere ◽  
Magnetic Field Generation ◽  
Plasma Dynamics ◽  
Electron Positron ◽  
Instability Development ◽  
Aperiodic Instability

AbstractSome aspects of relativistic electron-positron plasma dynamics in the pulsar magnetosphere are discussed. Namely it is shown that if we take into account the influence of centrifugal force, this gives rise to the new dynamical effect of plasma particle radial braking in the pulsar magnetosphere. Also the possibility of aperiodic instability development in the pulsar magnetosphere is demonstrated. The mechanism for the toroidal magnetic field generation is proposed. Besides, the possible changes of the pulsar magnetosphere structure caused by above mentioned processes is considered.

Propagation of nonlinear waves in a plasma in a magnetic field

1968 ◽  
Vol 2 (2) ◽  
pp. 105-118 ◽  
Author(s):  
Jeffrey P. Freidberg
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Waves ◽  
Local Density ◽  
Travelling Wave ◽  
Travelling Wave Solutions ◽  
Resonant Frequencies ◽  
Wave Solutions ◽  
Nonlinear Dispersion Relation ◽  
The Waves ◽  
The Magnetic Field

The propagation of nonlinear electromagnetic waves in a plasma is investigated by seeking travelling wave solutions to the macroscopic plasma equations. The model considered is that of a warm, anisotropic electron plasma in a magnetic field, in which the waves are allowed to propagate at any angle with respect to the magnetic field. A nonlinear dispersion relation is obtained which is valid for frequencies sufficiently close to the resonant frequencies. Travelling wave solutions are found for all amplitudes for which the local density remains positive. Also in sufficiently anisotropic plasmas the nature (i.e. propagating or cut-off) of one of the resonant waves can depend upon the amplitude.

scholarly journals Numerical simulation of Raman and Brillouin laser-pulse amplification in a magnetized plasma

2016 ◽  
Vol 34 (2) ◽  
pp. 315-337 ◽  
Author(s):  
Magdi Shoucri
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Waves ◽  
Distribution Functions ◽  
Magnetized Plasma ◽  
Numerical Code ◽  
Seed Pulse ◽  
Pulse Amplification ◽  
Laboratory Plasmas ◽  
Electrons And Ions ◽  
Amplification Process

AbstractWe apply an Eulerian Vlasov code to study the amplification of an ultra-short seed pulse via stimulated Raman and Brillouin backscattering of energy from a long pump pulse, assumed at constant amplitude, in a plasma embedded in an external magnetic field. Detailed analysis of the spectra developed during the amplification process are presented, together with the evolution showing the pump depletion, accompanied by the counter-propagating seed-pulse amplification, compression and increased steepness of the waveform. In addition to the problem of the amplification of ultra-short seed pulses, there is an obvious academic interest in the study of problems of amplification of electromagnetic waves observed in many situations in laboratory plasmas and in the magnetosphere and other geophysical situations, such as in the environments of planets, where important variations in the presence and strength of magnetic fields are observed. The numerical code solves a one-dimensional relativistic Vlasov–Maxwell set of equations for a plasma in a magnetic field for both electrons and ions. We also apply the code to the problem of wakefield acceleration. The absence of noise in the Eulerian Vlasov code allows one to follow the evolution of the system with an accurate representation of the phase-space structures of the distribution functions.

Electromagnetic waves emitted from an electron-positron plasma cloud moving across a magnetic field

1996 ◽  
Vol 53 (6) ◽  
pp. 6376-6381 ◽  
Author(s):  
Tadashi Kitanishi ◽  
Jun-Ichi Sakai ◽  
Ken-Ichi Nishikawa ◽  
Jie Zhao
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Waves ◽  
Plasma Cloud ◽  
Electron Positron

Using Compressibility and Electric Field to Characterize Circularly-Polarized Waves Near the Proton Cyclotron Frequency Observed by Solar Orbiter

2021 ◽  
Author(s):  
Yuri Khotyaintsev ◽  
Daniel B Graham ◽  
Konrad Steinvall ◽  
Andris Vaivads ◽  
Milan Maksimovic ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Electric Field ◽  
Electromagnetic Waves ◽  
Cyclotron Frequency ◽  
Density Fluctuations ◽  
Background Magnetic Field ◽  
The Waves ◽  
The Magnetic Field ◽  
Proton Cyclotron

<p>We report Solar Orbiter observations of electromagnetic waves near the proton cyclotron frequency during the first perihelion. The waves have polarization close to circular and have wave vectors closely aligned with the background magnetic field. Such waves are potentially important for heating of the solar wind as their frequency and polarization allows effective energy exchange with solar wind protons. The Radio and Plasma Waves (RPW) instrument provides a high-cadence measurement of plasma density and electric field which we use together with the magnetic field measured by MAG to characterize these waves. In particular we compute the compressibility and the phase between the density fluctuations and the parallel component of the magnetic field, and show that these have a distinct behavior for the waves compared to the Alfvénic turbulence. We compare the observations to multi-fluid plasma dispersion and identify the waves modes corresponding to the observed waves. We discuss the importance of the waves for solar wind heating.</p>

scholarly journals Bow shock specularly reflected ions in the presence of low-frequency electromagnetic waves: a case study

2004 ◽  
Vol 22 (7) ◽  
pp. 2325-2335 ◽  
Author(s):  
K. Meziane ◽  
C. Mazelle ◽  
M. Wilber ◽  
D. LeQuéau ◽  
J. P. Eastwood ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Angular Distribution ◽  
Electromagnetic Waves ◽  
Specular Reflection ◽  
Bow Shock ◽  
Magnetic Field Direction ◽  
Angle Distribution ◽  
Production Mechanism ◽  
High Count ◽  
The Waves

Abstract. An energetic ion (E≤40) event observed by the CLUSTER/CIS experiment upstream of the Earth's bow shock is studied in detail. The ion event is observed in association with quasi-monochromatic ULF MHD-like waves, which we show modulate the ion fluxes. According to three statistical bow shock position models, the Cluster spacecrafts are located at ~0.5 Re from the shock and the averaged bow shock θBn0 is about ~30°. The analysis of the three-dimensional angular distribution indicates that ions propagating roughly along the magnetic field direction are observed at the onset of the event. Later on, the angular distribution is gyrophase-bunched and the pitch-angle distribution is peaked at α0~θBn0, consistent with the specular reflection production mechanism. The analysis of the waves shows that they are left-handed in the spacecraft frame of reference (right-handed in the solar wind frame) and propagate roughly along the ambient magnetic field; we have found that they are in cyclotron-resonance with the field-aligned beam observed just upstream. Using properties of the waves and particles, we explain the observed particle flux-modulation in the context of θBn changes at the shock caused by the convected ULF waves. We have found that the high count rates coincide with particles leaving the shock when θBn angles are less than ~40°, consistent with the specular reflection hypothesis as the production mechanism of ions.

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