Electromagnetic Darwin Model for High Intensity Beams
Abstract
This paper explores the advantages of using the canonical momentum, P ≡ p + q A/c, in the laboratory frame for the electromagnetic Darwin model of the Maxwell-Vlasov system, for which the transverse displacement current is neglected in Ampere's law. Here, A is the vector potential and p is the mechanical momentum. With the new formulation, we not only can eliminate the high-frequency transverse electromagnetic effects from the system as intended by the Darwin model, but also can get rid of the numerically troublesome partial A / partial t term for particle pushing. (C. W. Nielson and H. R. Lewis, Methods in Computational Physics) (Academic Press, New York, 1976), Vol. 16, p. 976. The formulation is most useful for studying space-charge effects in high-intensity multi-species beams using perturbative particle simulation methods, (W. W. Lee, Q. Qin and R. C. Davidson, Phys. Lett. A 230), 347 (1997). such as two-stream (H. Qin, R. C. Davidson and W. W. Lee, Phys. Rev. Special Topics on Accelerators amd beams 3), 08441 (2000); 3, 109901 (2000). and filamentation instabilities, that may cause deterioration of the beam quality in heavy ion fusion drivers and the fusion chamber. Moreover, the new formulation provides an easy link to the electrostatic model for a single-species beam in the beam frame. Initial numerical results will be reported.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- October 2001
- Bibcode:
- 2001APS..DPPFP1131L