Decay of nonlinear whistler mode waves: 1D versus 2D

Direct comparison between one-dimensional (1D) and two-dimensional (2D) models for the development of a nonlinear, short-wavelength, and monochromatic electromagnetic whistler mode wave is made by means of fully electromagnetic particle-in-cell simulations. The 1D and 2D simulations are performed for low beta conditions in which the plasma pressure is much lower than the magnetic pressure, although the plasma kinetic energy in the direction perpendicular to the ambient magnetic field is highly dominant due to the velocity field of the imposed parent whistler mode wave. A three-wave parametric decay of the parent whistler mode wave was reconfirmed in the 1D simulation. On the other hand, a rapid decay of the parent whistler mode wave thorough a five-wave interaction or double three-wave interactions was seen in the 2D simulation. Electron heating processes in the 2D simulation are also different from those in the 1D simulation. It is suggested that the present 2D decay process is a new instability which is quite different from velocity space instabilities driven by temperature/energy anisotropy. Published by AIP Publishing.