Weakly nonlinear ion sound waves in gravitational systems
Abstract
Ion sound waves are studied in a plasma subject to gravitational field giving rise to vertically inhomogeneous steady-state plasma conditions. Such systems are interesting by exhibiting a wave growth that is a result of energy flux conservation for pulses propagating in an inhomogeneous system. The increase of the amplitude of a pulse as it propagates along the density gradient in the direction of decreasing density gives rise to an enhanced interaction between waves and plasma particles that can be modeled by a modified Korteweg-de Vries equation. Analytical results are compared with numerical particle-in-cell simulations of the problem. Our code assumes isothermally Boltzmann distributed electrons resulting in a nonlinear Poisson equation. The ion component is treated as a collection of individual particles interacting through collective electric fields. Deviations from quasineutrality are allowed for.
- Publication:
-
Physical Review E
- Pub Date:
- April 2020
- DOI:
- 10.1103/PhysRevE.101.043210
- arXiv:
- arXiv:1912.09173
- Bibcode:
- 2020PhRvE.101d3210G
- Keywords:
-
- Physics - Plasma Physics
- E-Print:
- 30 pages, 9 figures