Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Physics
Decay Of Trapped-Particle Asymmetry Modes In Non-Neutral Plasmas In A Malmberg-Penning Trap, Grant W. Mason
Decay Of Trapped-Particle Asymmetry Modes In Non-Neutral Plasmas In A Malmberg-Penning Trap, Grant W. Mason
Faculty Publications
The mechanism for the strong damping of diocotron-like azimuthal trapped-particle asymmetry modes in a Malmberg-Penning trap is investigated with a detailed three-dimensional particle-in-cell computer simulation. The m = 1,kzis not equal to 0 modes are created by a voltage squeeze from a mid-detector ring followed by a displacement of trapped particles in opposite directions on either side of the ring. The voltage squeeze creates a population of particles confined to half the trap length (trapped) and a population of particles that move longitudinally along the full length of the cylinder (untrapped). The damping of the modes is found to be …
Modes In A Non-Neutral Plasma Of Finite Length, M = 0,1, S. Neil Rasband, Ross L. Spencer
Modes In A Non-Neutral Plasma Of Finite Length, M = 0,1, S. Neil Rasband, Ross L. Spencer
Faculty Publications
For realistic, cold equilibria of finite length representing a pure electron plasma confined in a cylindrical Malmberg–Penning trap, the mode spectrum for Trivelpiece–Gould, m=0, and for diocotron, m=1, modes is calculated numerically. A novel method involving finite elements is used to successfully compute eigenfrequencies and eigenfunctions for plasma equilibria shaped like pancakes, cigars, long cylinders, and all things in between. Mostly sharp-boundary density configurations are considered but also included in this study are diffuse density profiles including ones with peaks off axis leading to instabilities. In all cases the focus has been on elucidating the role of finite length in …