| Paper | Title | Page |
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| THPC100 | Collisionless Relaxation in the Transport of Space Charge Dominated Beams | 3209 |
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Relaxation to a final stationary state of particles interacting through long-range forces, such as Coulomb, is intrinsically different than that of systems with short-range interactions. While in the latter case it is known that the interparticle collisions drive the system to an equilibrium Maxwell-Boltzmann distribution, in the former case, the collision duration time diverges and the state of thermodynamic equilibrium is never reached. In this paper, a theory is presented which allows to quantitatively predict the final stationary state achieved by a transported space-charge dominated beam during a process of collisionless relaxation*. It is shown that a fully matched beam relaxes to a Fermi-Dirac distribution. However, when a mismatch is present and the beam oscillates, halo formation leads to a phase separation. The theory developed allows to quantitatively predict both the density and the velocity distributions in the final stationary state, including the halo.
* Y. Levin, R. Pakter, and T. N. Teles, Phys. Rev. Lett., 100, 040604 (2008). |
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| THPC103 | Wave Breaking and Test Particle Dynamics in Inhomogeneous Beams | 3218 |
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| This work analyzes the dynamics of inhomogeneous, magnetically focused high-intensity beams of charged particles. While for homogeneous beams the whole system oscillates with a single frequency, any inhomogeneity leads to propagating transverse density waves which eventually result in a singular density build up, causing wave breaking and jet formation. Wave breaking is shown to relax the mismatched beam and we make use of Lynden-Bell's theory of violent relaxation to estimate characteristics of the relaxed state. |