scholarly journals The Axisymmetric Pulsar Magnetosphere: A Classical Model

1992 ◽  
Vol 128 ◽  
pp. 96-97
Author(s):  
R. Fitzpatrick ◽  
L. Mestel
Keyword(s):  
Magnetic Force ◽  
Classical Model ◽  
Polar Regions ◽  
Electric Force ◽  
Poloidal Field ◽  
Pulsar Magnetosphere ◽  
Classical Physics ◽  
Field Lines ◽  
Current Flows ◽  
The Moment

The aim of this work (Fitzpatrick and Mestel 1988a, Fitzpatrick and Mestel 1988b) is to elucidate how a neutron star with a dipolar magnetic field of axis k and an instantaneous angular velocity αk would spin down, within the framework of classical physics. The rotation of the highly conducting stellar crust generates differences of electric potential between field lines. An electron current flows from points of lower to higher potential via a dissipation domain located largely beyond the light-cylinder. Electrons leave the star's polar regions as a subrelativistic stream, flowing nearly along the lines of the poloidal field Bp, picking up energy from the electric force and angular momentum from the moment about k of the magnetic force.

scholarly journals Equilibrium of the Return-Current Sheet and Structure of the Pulsar Magnetosphere

1992 ◽  
Vol 128 ◽  
pp. 112-113
Author(s):  
Yu. E. Lyubarskii
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Neutron Stars ◽  
Current Sheet ◽  
Equilibrium Condition ◽  
Pulsar Magnetosphere ◽  
Field Lines ◽  
Current Flows ◽  
Magnetic Poles ◽  
Open Magnetic Field

Pulsars are generally identified with rotating, magnetized neutron stars. According to Goldreich and Julian (1969), an induced electric field creates the electric current which flows out of the magnetic poles and fills the magnetosphere with plasma. The current flows along the open magnetic field lines and returns along the boundary between the closed and open parts of the magnetosphere (Scharlemann and Wagoner 1973). The boundary shape is determined by the equilibrium condition for the current sheet.

scholarly journals Beam instabilities in a magnetized pair plasma

1999 ◽  
Vol 62 (1) ◽  
pp. 65-86 ◽  
Author(s):  
MAXIM LYUTIKOV
Keyword(s):  
Growth Rates ◽  
Particle Interaction ◽  
Kinetic Regime ◽  
Pulsar Magnetosphere ◽  
Pair Plasma ◽  
Electron Positron ◽  
Pulsar Radiation ◽  
Radiation Generation ◽  
Field Lines ◽  
Beam Instabilities

Beam instabilities in the strongly magnetized electron–positron plasma of a pulsar magnetosphere are considered. We analyse the resonance conditions and estimate the growth rates of the Cherenkov and cyclotron instabilities of the ordinary (O), extraordinary (X) and Alfvén modes in two limiting regimes: kinetic and hydrodynamic. The importance of the different instabilities as a source of coherent pulsar radiation generation is then estimated, taking into account the angular dependence of the growth rates and the limitations on the length of the coherent wave–particle interaction imposed by the curvature of the magnetic field lines. We conclude that in the pulsar magnetosphere, Cherenkov-type instabilities occur in the hydrodynamic regime, while cyclotron-type instabilities occur in the kinetic regime. We argue that electromagnetic cyclotron-type instabilities on the X, O and probably Alfvén waves are more likely to develop in the pulsar magnetosphere.

scholarly journals Electron Outflow in Axisymmetric Pulsar Magnetospheres

1985 ◽  
Vol 38 (5) ◽  
pp. 749 ◽  
Author(s):  
RR Burman
Keyword(s):  
Magnetic Field ◽  
Pulsar Magnetosphere ◽  
Poloidal Magnetic Field ◽  
Light Cylinder ◽  
Field Lines ◽  
Limiting Surface

Mestel et al. (1985) have recently introduced an axisymmetric pulsar magnetosphere model in which electrons leave the star with speeds that are non-negligible, but not highly relativistic, and flow with moderate acceleration, and with poloidal motion that is closely tied to the poloidal magnetic field lines, before reaching a limiting surface, near which rapid acceleration occurs. This paper presents an analysis of flows which either encounter the limiting surface beyond the light cylinder or do not meet it at all.

scholarly journals XVII. Contributions to terrestrial magnetism. — No. VII

1846 ◽  
Vol 136 ◽  
pp. 237-336 ◽  
Keyword(s):  
New York ◽  
Magnetic Force ◽  
The Arctic ◽  
General View ◽  
Magnetic Survey ◽  
Terrestrial Magnetism ◽  
North American Continent ◽  
The North ◽  
Common Unit ◽  
The Moment

Containing a Magnetic Survey of a considerable portion of the North American Continent. From the moment that the fact was known, that the locality of the maximum of the magnetic Force in a hemisphere is not coincident, as was previously supposed, with the locality where the dip of the needle is 90°, researches in terrestrial magnetism assumed an interest and importance greatly exceeding that which they before pos­sessed; for it was obvious that the hypothesis which then generally prevailed regard­ing the distribution of the magnetic Force at the surface of the globe, and which had been based on a too-limited induction, was erroneous, and that even the broad out­ line of the general view of terrestrial magnetism had to be recast. The observations on which this discovery rested, (being those which I had had an opportunity of making in 1818, 1819 and 1820 within the Arctic Circle, and at New York in 1822,) were published in 1825*; they constituted, I may be permitted to say, an important feature in the views, which led the British Association in the year 1835 to request that a report should be prepared, in which the state of our knowledge in respect to the variations of the magnetic Force at different parts of the earth’s sur­face should be reviewed, and, as is customary in the reports presented to that very useful institution, that those measures should be pointed out which appeared most desirable for the advancement of this branch of science. In the maps attached to the report, the isodynamic lines on the surface of the globe were drawn simply in conformity with observations, and unmixed with hypothesis of any sort. The obser­vations collected for that purpose were not those of any particular individual or of any single nation, but embodied the results obtained by all persons who up to that period had taken part in such researches, subjected to such amount of discussion only as conveyed a knowledge of the modes of observation severally employed, and reduced the whole to a common unit.

scholarly journals Water on Venus?

1971 ◽  
Vol 40 ◽  
pp. 55-61
Author(s):  
W. F. Libby ◽  
P. Corneil
Keyword(s):  
Carbon Dioxide ◽  
Liquid Water ◽  
Black Body ◽  
Lower Latitude ◽  
Polar Regions ◽  
Water Ice ◽  
Evaporation And Condensation ◽  
Dust Clouds ◽  
Body Surface Temperature ◽  
The Moment

It is proposed that Venus may have polar seas which are acidic and thus cannot precipitate calcium carbonate. This leaves the carbon dioxide in the atmosphere. The argument is that the great equatorial land masses always have been too hot for liquid water and thus could not be weathered to give the sea salts necessary to form the precipitate. The action of steam on rocks is to liberate acids which are volatile and would dissolve in the polar seas. The volcanic vapors issuing in the early times consisting mainly of water and carbon dioxide would have begun polar seas at once since the expected equatorial (black body) surface temperature of the bare planet is too high (464 K) due to proximity of the sun. The accumulation of carbon dioxide in the atmosphere would have ensured the continued increase of the temperature due to the greenhouse effect. On earth, on the contrary, condensation over most of the planetary surface probably was possible from the beginning. Liquid water, ice-weathering, and river transport of salts to the seas all probably occurred from the beginning.As the pressure at the surface probably approximates 100 atm (Venera 5 and 6) we can expect the polar seas to be below the boiling point although possibly hot. An isothermal layer of some thickness is naturally established over liquid water heated by infrared from above. Evaporation and condensation to form rain constitutes an efficient heat transport mechanism. Such a layer naturally would move toward lower latitude carrying moisture which then will rise and eventually move poleward in the high atmosphere causing rain and possibly the planet wide cloud cover. The atmosphere containing volatiles such as hydrochloric and hydrofluoric and sulfurous and sulfuric acids as well as carbon dioxide will form clouds which might be expected to consist of concentrated acid solutions. The main rain over the poles probably falls from altitudes well below the cloud top seen from earth. It is possible that the Venus clouds seen from earth are non aqueous just as our stratosphere carries dust clouds apparently of ammonium sulfate. At the moment it is very difficult to decide between these alternatives.In the more polar regions the seas might conceivably be as cool as 50 °C.

scholarly journals Pulsar Electrodynamics — Pulsars and Puzzlers —

1996 ◽  
Vol 160 ◽  
pp. 409-416
Author(s):  
Shinpei Shibata
Keyword(s):  
Magnetic Field ◽  
Pair Creation ◽  
Gap Model ◽  
Pulsar Magnetosphere ◽  
Wind Model ◽  
Gedanken Experiment ◽  
Basic Understanding ◽  
Free Parameters ◽  
Pulsar Wind ◽  
Field Lines

AbstractA gedanken experiment presented here provides basic understanding of how the pulsar magnetosphere operates. We discuss current issues about the electric-field acceleration along magnetic field lines and subsequent pair creation, and also about the pulsar wind problem. It is stressed that any local model, such as the inner gap model, the outer gap model and the pulsar wind model, must have free parameters to link it to other part of the magnetosphere.

scholarly journals Integrals of the equations of electrodynamics with to the electric constants of a transparent medium

1926 ◽  
Vol 113 (764) ◽  
pp. 237-253 ◽  
Keyword(s):  
Electric Current ◽  
Current Distribution ◽  
Magnetic Force ◽  
Small Radius ◽  
Transparent Medium ◽  
Electric Force ◽  
Present Communication ◽  
Magnetic Current ◽  
Magnetic Forces ◽  
Equations Of Electrodynamics

Integrals of the equations of propagation of electrical disturbances have been given by the present writer which express the electric and magnetic forces at any point outside a surface enclosing all the sources in terms of an electric current distribution and a magnetic current distribution over the surface. The result for a source at a point can be obtained by taking as the surface a sphere of very small radius with its centre at the point. This suggests that the equations representing Faraday’s laws can be written 1/V 2 ∂X/∂ t +4π i x = ∂ϒ/∂ y – ∂β/∂ z , 1/V 2 ∂X/∂ t + 4π i v =∂∝/∂ z – ∂ϒ/∂ x , 1/V 2 ∂z/∂ t – 4π i z = ∂β/∂ x – ∂∝/∂ y (1) – ∂∝/∂ t + 4π m x = ∂z/∂ y – ∂Y/∂y, – ∂β/∂t + 4π my = ∂X/∂ z – ∂Z/∂ x , – ∂ϒ/∂ t + 4π mz ∂Y/∂ x – ∂X/∂ y , (2) where X, Y, Z are the components of the electric force, α, β, γ are the components of the magnetic force, i x , i y , i z are the components of an electric current distribution, and m x , m y , m z are the components of a magnetic current distribution throughout the space. The object of the present communication is to express X, Y, Z, α, β, γ in terms of the electric current and magnetic current distributions and to apply the result to the discussion of the electric constants of a transparent medium. It is convenient to take instead of equations (1) and (2) the following equations, which include (1) and (2) as a particular case

scholarly journals The diffusion and mobility of ions in a magnetic field

1912 ◽  
Vol 86 (590) ◽  
pp. 571-577 ◽  
Keyword(s):  
Magnetic Field ◽  
Free Path ◽  
Magnetic Force ◽  
Mean Free Path ◽  
Electric Force ◽  
Mobility Of Ions ◽  
The Mean ◽  
The Magnetic Field

1. When the motion of ions in a gas takes place in a magnetic field the rates of diffusion and the velocities due to an electric force may be determined by methods similar to those given in a previous paper. The effect of the magnetic field may be determined by considering the motion of each ion between collisions with molecules. The magnetic force causes the ions to be deflected in their free paths, and when no electric force is acting the paths are spirals, the axes being along the direction of the magnetic force. If H be the intensity of the magnetic field, e the charge, and m the mass of an ion, then the radius r of the spiral is mv /He, v being the velocity in the direction perpendicular to H. The distance that the ion travels in the interval between two collisions in a direction normal to the magnetic force is a chord of the circle of radius r . The average lengths of these chords may be reduced to any fraction of the projection of the mean free path in the direction of the magnetic force, so that the rate of diffusion of ions in the directions perpendicular to the magnetic force is less than the rate of diffusion in the direction of the force.

scholarly journals The transmission of electric waves around the Earth's surface

1916 ◽  
Vol 92 (643) ◽  
pp. 493-500 ◽  
Keyword(s):  
General Formula ◽  
Magnetic Force ◽  
Wave Length ◽  
Angular Distance ◽  
Electric Force ◽  
Present Communication ◽  
The Earth ◽  
Perfect Conduction ◽  
Electric Waves

The value of the magnetic force at a point on the earth's surface, due to a simple oscillator placed on the surface with its axis normal to the surface, has been recently calculated by Love for a wave-length of 5 kilom. at certain distances from the oscillator. His results for the case of perfect conduction are the same as the corresponding series when the surface of the earth is supposed to be imperfectly conducting, The object of the present communication is to obtain the general formula for the case of imperfect conduction. Let r, θ, ϕ be the polar co-ordinates of a point, where r is its distance from the centre of the earth, θ its angular distance from the oscillator, E r , E θ , E ϕ the components of the electric force, and α, β, γ , the corresponding components of the magnetic force. Then, Since there is symmetry round the axis of the oscillator, α =0, β =0, γ =0; and throughout space outside the surface

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