Nonlinear Interactions of Alfven Waves in Multi-ion Plasmas
Abstract
Nonlinear behaviors of Alfven waves, such as parametric decay and wave-wave interaction, are important in the low-beta plasmas solar wind. They can contribute to turbulence development and dissipation of wave energy. Despite their important role in natural plasmas, laboratory verification of these processes has not been fully established. Here, we present our recent experiments on LAPD, investigating nonlinear interactions of two counter-propagating Alfven waves in a plasma with both hydrogen and helium ions. The results show that a third Alfven wave can be excited through three wave resonance. The presence of a second ion species not only changes the linear dispersion relation of the Alfven-cyclotron wave, but also opens up more channels for nonlinear interaction. This study may find applications in the solar wind near the Sun, where the presence of a significant amount of helium ions can change the dynamics of Alfven waves. Three wave resonance also offers an alternative method of determining the relative density of each ion species in laboratory experiments.
- Publication:
-
Solar Heliospheric and INterplanetary Environment (SHINE 2019)
- Pub Date:
- May 2019
- Bibcode:
- 2019shin.confE.213F