Electromagnetic jets in pulsar magnetospheres and near magnetized accretion disks
The author studied the structure of the electromagnetic fields that surround a rotating, magnetized neutron star or that may be in and near the accretion disk of an active galactic nucleus. He uses the method developed for time-independent axisymmetric fusion plasma equilibria the Grad-Shafranov equation. This procedure allows one to apply a powerful result from fusion plasma equilibria to constrain the form of the magnetic helicity for the configuration, Taylor's hypothesis. This removes an indeterminacy from the pulsar equation that has plagued all earlier attempts to find a unique equation to describe the fields. The pulsar equation is fixed to be a piecewise linear partial differential equation with a class of solutions that include self-collimated electromagnetic jets along the rotation axis of the star. These jets carry energy, angular momentum, and electric current away from the star. A finite-difference scheme is employed to solve for the entire field structure for these jet-magnetospheres. For the structure of the accretion disk fields, he first develops the formalism to describe the equilibria of a thin, viscous, resistive, and non-relativistic accretion disk, leading to simplified equations for the poloidal and toroidal magnetic field. He treats the coronal plasma that surrounds the disk like the magnetospheric plasma of the pulsar, and find a pulsar equation that determines the fields there. A Green's function method is used to determine the far-field solution for the coronal fields. Energy conservation for the disk-jet system yields a global consistency condition which restricts the amount of gravitational accretion power than can be carried away by the jets for a given field symmetry.
- Research Organization:
- Cornell Univ., Ithaca, NY (USA)
- OSTI ID:
- 6486642
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
ACCRETION DISKS
PLASMA JETS
PLANETARY MAGNETOSPHERES
PULSARS
ANGULAR MOMENTUM
ELECTRIC CURRENTS
ELECTROMAGNETIC FIELDS
ENERGY LOSSES
EQUILIBRIUM
FINITE DIFFERENCE METHOD
NEUTRON STARS
PARTIAL DIFFERENTIAL EQUATIONS
TIME DEPENDENCE
ATMOSPHERES
COSMIC RADIO SOURCES
CURRENTS
DIFFERENTIAL EQUATIONS
EQUATIONS
ITERATIVE METHODS
LOSSES
NUMERICAL SOLUTION
PLANETARY ATMOSPHERES
STARS
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources