The structure and statistics of interstellar turbulence
  We explore the structure and statistics of multiphase, magnetized ISM
turbulence in the local Milky Way by means of driven periodic box numerical MHD
simulations. Using the higher order-accurate piecewise-parabolic method on a
local stencil (PPML), we carry out a small parameter survey varying the mean
magnetic field strength and density while fixing the rms velocity to observed
values. We quantify numerous characteristics of the transient and steady-state
turbulence, including its thermodynamics and phase structure, kinetic and
magnetic energy power spectra, structure functions, and distribution functions
of density, column density, pressure, and magnetic field strength. The
simulations reproduce many observables of the local ISM, including molecular
clouds, such as the ratio of turbulent to mean magnetic field at 100 pc scale,
the mass and volume fractions of thermally stable HI, the lognormal
distribution of column densities, the mass-weighted distribution of thermal
pressure, and the linewidth-size relationship for molecular clouds. Our models
predict the shape of magnetic field probability density functions (PDFs), which
are strongly non-Gaussian, and the relative alignment of magnetic field and
density structures. Finally, our models show how the observed low rates of star
formation per free-fall time are controlled by the multiphase thermodynamics
and large-scale turbulence.
