||Non-MHD effects in the nonlinear development of the MHD-scale Rayleigh-Taylor instability
Takayuki, UmedaYasutaka, Wada
072307 , 2017-07-07 , AIP Publishing
The nonlinear evolution of the Rayleigh-Taylor instability (RTI) at a density shear layer transverseto magnetic field in a collisionless plasma is investigated by means of a fully kineticVlasov simulation with two spatial and two velocity dimensions. The primary RTI in the MHDregime develops symmetrically in a coordinate axis parallel to gravity as seen in the previousMHD simulations. The primary RTI in the Hall-MHD regime develops asymmetrically in acoordinate axis parallel to gravity. A compressible flow is formed at the secondary density shearlayer by the Hall effect, which generates a strong scalar pressure gradient of ions. A Hall electricfield due to the diamagnetic current results in the asymmetric flow at the tip of the finger structure.In the primary RTI with the ion gyro kinetic effect, secondary RTI with a wavelengthshorter than the wavelength of the primary RTI is generated at the saturation stage of the primaryRTI. A seed perturbation for the secondary RTI is excited by another secondary instabilitydue to the coupling between the electron stress tensor and the Hall electric field. The heatflux term plays an important role in the time development of the total pressure. On the otherhand, the contribution of the ion stress tensor is small in both the electric current and the totalpressure.