Effects of plasma kinetic parameters on turbulent layer formation by the Kelvin-Helmholtz instability

Details Effects of plasma kinetic parameters on turbulent layer formation by the Kelvin-Helmholtz instability Effects of plasma kinetic parameters on turbulent layer formation by the Kelvin-Helmholtz instability

Dec 2010

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010agufmsm51b1799m&link_type=abstract

American Geophysical Union, Fall Meeting 2010, abstract #SM51B-1799

Physics

Plasma Physics

[2724] Magnetospheric Physics / Magnetopause And Boundary Layers, [7839] Space Plasma Physics / Nonlinear Phenomena, [7859] Space Plasma Physics / Transport Processes, [7863] Space Plasma Physics / Turbulence

Scientific paper

We have recently shown by 2D MHD simulations of the Kelvin-Helmholtz instability (KHI) in a highly asymmetric density layer in a large simulation domain that rapid formation of a broad plasma turbulent layer can be achieved by forward and inverse energy cascades of the KHI [Matsumoto and Seki, JGR, in press.]. The forward cascade is triggered by the growth of the secondary Rayleigh-Taylor instability (RTI) excited during the nonlinear evolution. The inverse cascade is accomplished by a nonlinear coupling of the fastest growing mode of the KHI with other unstable modes. We suggested that the proposed mechanism well explained the observational requirements of the LLBL formation, although some issues are remained to be understood. One major issue, which is not treated accurately in the MHD simulation, is the mixing process itself; the mixing of plasmas is due to the numerical dissipation implicitly or explicitly added in the simulation. To understand all the mechanisms ranging from the dissipating scale to the scale of the largest vortex in a self-consistent manner, we have carried out 2D fully kinetic particle-in-cell (PIC) simulations of the KHI in a large simulation domain which allows growth of multiple KH unstable modes. As a result, we found the inverse energy cascade among the KH unstable modes as have been shown by the 2D MHD simulation. It is also found that the direct energy cascade results in plasma mixing by exciting strong electric fields embedded in electron inertial scales with amplitudes larger than the initial convective electric field. The locally excited electric field is the key agent for the mixing. We have also found two-component distribution functions in the mixed region for the ion and the electron which have been reported by in-situ observations. In this presentation, we show that both direct and inverse energy cascades of the KHI contribute to formation of a large scale plasma mixing layer in a time scale much faster than we expect from the linear theory of the KHI. Also, dependence of the mixing efficiency on the mass ratio (M/m) and the ratio of plasma to gyro frequencies (ωpe/Ωge) are discussed by results from simulation runs with various kinetic parameters.

Affiliated with

Also associated with

No associations

Rating

Effects of plasma kinetic parameters on turbulent layer formation by the Kelvin-Helmholtz instability does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Effects of plasma kinetic parameters on turbulent layer formation by the Kelvin-Helmholtz instability, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Effects of plasma kinetic parameters on turbulent layer formation by the Kelvin-Helmholtz instability will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1473622