Wave production in an ultrarelativistic electron-positron plasma

Journal Article · Sun Jan 01 00:00:00 EST 1978 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/155774· OSTI ID:5164456

Hardee, P E; Rose, W K

In this paper we calculate the eigenmodes associated with an ultrarelativistic electron-positron beam traversing a low-energy electron-positron plasma under physical conditions that may exist along open magnetic field lines above pulsar polar caps. We assume that both beam and plasma are cold and charge neutral, and that magnetic field strength and particle density decrease as (1/R)/sup 3/. In the superstrong magnetic fields near the stellar surface where cyclotron frequencies exceed plasma frequencies, electrostatic waves and associated transverse low-frequency waves are driven unstable by the two-stream type particle distribution. At larger distances above the stellar surface the slow beam cyclotron wave is driven unstable. At even greater radial distance (approximately when particle energy density exceeds magnetic energy density) both the Ordinary and Alfven modes become unstable. All of these instabilities can lead to generation of radiation. If the particle distribution as generated at the stellar surface, assumed to consist of two streams, is modified only by plasma effects, then electrostatic and associated transverse waves may only be unstable near the stellar surface. The beam cyclotron mode which is driven by a two-stream or an inverted particle distribution may be stable. The Ordinary and Afven modes will probably be unstable provided the particles remain cold perpendicular to the magnetic field. The wave modes most likely to play a role in the generation of pulsar radiation are the electrostatic and the associated transverse low-frequency waves generated near the surface and the Ordinary mode provided it becomes unstable within the light cylinder.

• Research Organization: Astronomy Program, University of Maryland
• OSTI ID: 5164456
• Journal Information: Astrophys. J.; (United States), Vol. 219:1
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
PULSARS
PLASMA WAVES
ALFVEN WAVES
BEAM-PLASMA SYSTEMS
CYCLOTRON FREQUENCY
DISPERSION RELATIONS
EIGENSTATES
ELECTRONS
MAGNETIC FIELDS
POSITRONS
RELATIVISTIC RANGE
STAR MODELS
TWO-STREAM INSTABILITY
WAVE PROPAGATION
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
COSMIC RADIO SOURCES
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
HYDROMAGNETIC WAVES
INSTABILITY
LEPTONS
MATHEMATICAL MODELS
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
640103* - Astrophysics & Cosmology- Quasi-Stellar
Radio
& X-Ray Sources- (-1987)