Charged-Particle Motion in Electromagnetic Fields Having at Least One Ignorable Spatial Coordinate
Abstract
We give a rigorous derivation of a theorem showing that charged particles in an arbitrary electromagnetic field with at least one ignorable spatial coordinate remain forever tied to a given magnetic field line. Such a situation contrasts with the significant motions normal to the magnetic field that are expected in most real three-dimensional systems. It is pointed out that while the significance of the theorem has not been widely appreciated, it has important consequences for a number of problems and is of particular relevance for the acceleration of cosmic rays by shocks.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 1998
- DOI:
- 10.1086/306480
- arXiv:
- arXiv:astro-ph/9808103
- Bibcode:
- 1998ApJ...509..238J
- Keywords:
-
- ACCELERATION OF PARTICLES;
- ISM: COSMIC RAYS;
- METHODS: ANALYTICAL;
- MAGNETOHYDRODYNAMICS: MHD;
- Acceleration of Particles;
- ISM: Cosmic Rays;
- Methods: Analytical;
- Magnetohydrodynamics: MHD;
- Astrophysics
- E-Print:
- 7 pages, emulateapj format, including 1 eps figure, to appear in The Astrophysical Journal, Dec. 10 1998 issue