HR: 1340h
AN: ED43A-0272    [Abstracts]
TI: Wave and Plasma Simulations
AU: Lazos, J
EM: jbushhead@comcast.net
AF: Pinkerton Academy High School, 5 Pinkerton St., Derry, NH 03038 United States
AU: * Vasquez, B J
EM: bernie.vasquez@unh.edu
AF: University of New Hamsphire, Space Science Center, Durham, NH 03824 United States
AB: Rapidly moving streams of plasma emanate from the Sun and team with long magnetized waves which are called Alfven waves. The waves have sharp edges showing evidence of nonlinear wave steepening. They are also arc-polarized wherein the total magnetic intensity is a constant but the magnetic field direction sweeps back and forth along a circular arc like a wiper-blade. The solar-wind plasma is nearly collisionless and shows evidence of preferred ion heating. There are also distinct beams of various atoms which stream relative to the main component of solar-wind protons. The detailed individual motions of the ions are important to follow in order to understand the behavior of the plasma and waves. We employ hybrid numerical simulations using particle ions and fluid electrons. We present results from 3 simulation projects which will demonstrate how small but resonant forces can cumulatively lead to large changes: (1) Small amplitude and linearly polarized Alfven waves propagating parallel to the background magnetic field nonlinearly steepen. We have measured the time of steepening as a function of the ratio of plasma to magnetic pressure, especially for ratios of order unity where analytical calculations cannot determine the steepening time. (2) Arc-polarized Alfven waves can propagate without changing form, but we show that small disturbances can lead to their decay into new waves. (3) Beams of ions streaming relative to one another can drive up waves from the smallest starting disturbances. We show that this slows the relative streaming speed below a threshold where the speed becomes steady. This work was completed at the University of New Hampshire through the Science and Mathematics Achievement through Research Training (SMART) program.
DE: 7827 Kinetic and MHD theory
DE: 7843 Numerical simulation studies
DE: 7867 Wave/particle interactions
DE: 7871 Waves and instabilities
DE: 2149 MHD waves and turbulence
SC: Education and Human Resourcese [ED]
MN: 2004 AGU Fall Meeting