Bobbing and kicks in electromagnetism and gravity
- Enrico Fermi Institute and Department of Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637 (United States)
We study systems analogous to binary black holes with spin in order to gain some insight into the origin and nature of 'bobbing' motion and 'kicks' that occur in this system. Our basic tool is a general formalism for describing the motion of extended test bodies in an external electromagnetic field in curved spacetime and possibly subject to other forces. We first show that bobbing of exactly the type as observed in numerical simulations of the binary black hole system occurs in a simple system consisting of two spinning balls connected by an elastic band in flat spacetime. This bobbing may be understood as arising from the difference between a spinning body's 'lab frame centroid' and its true center of mass, and is purely 'kinematical' in the sense that it will appear regardless of the forces holding two spinning bodies in orbit. Next, we develop precise rules for relating the motion of charged bodies in a stationary external electromagnetic field in flat spacetime with the motion of bodies in a weakly curved stationary spacetime. We then consider the system consisting of two orbiting charges with magnetic dipole moment and spin at a level of approximation corresponding to 1.5 post-Newtonian order. Here we find that considerable amounts of momentum are exchanged between the bodies and the electromagnetic field; however, the bodies store this momentum entirely as ''hidden'' mechanical momentum, so that the interchange does not give rise to any net bobbing. The net bobbing that does occur is due solely to the kinematical spin effect, and we therefore argue that the net bobbing of the electromagnetic binary is not associated with possible kicks. We believe that this conclusion holds in the gravitational case as well.
- OSTI ID:
- 21409731
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 81, Issue 10; Other Information: DOI: 10.1103/PhysRevD.81.104012; (c) 2010 The American Physical Society; ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
Similar Records
Kick processes in the merger of two colliding black holes
Superkicks in ultrarelativistic encounters of spinning black holes
Related Subjects
COSMOLOGY AND ASTRONOMY
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
APPROXIMATIONS
BINARY STARS
BLACK HOLES
CENTER-OF-MASS SYSTEM
COMPUTERIZED SIMULATION
ELECTROMAGNETIC FIELDS
ELECTROMAGNETISM
GAIN
GRAVITATION
MAGNETIC DIPOLE MOMENTS
SPACE-TIME
SPIN
AMPLIFICATION
ANGULAR MOMENTUM
CALCULATION METHODS
DIPOLE MOMENTS
MAGNETIC MOMENTS
MAGNETISM
PARTICLE PROPERTIES
SIMULATION
STARS