Physics Dept Seminar

February 26, Wednesday (*SPECIAL DAY*)

On the Radial Evolution of Magnetohydrodynamic Turbulence in the Solar Atmosphere and Solar Wind

Prof. Jean C. Perez

Florida Institute of Technology

(Theoretical Solar Physics, Host: Cao)

*SPECIAL TIME: 2:45 pm - 3:45 pm with 2:30 pm teatime

*SPECIAL ROOM: FMH 408

In this work I will present recent results from high-resolution direct numerical simulations and phenomenological modeling of reflection-driven Magnetohydrodynamic (MHD) turbulence in the near-Sun solar wind. The simulations describe Alfvenic fluctuations within a narrow coronal hole extending from the photosphere out to a heliocentric distance of approximately ninety solar radii. Large-scale Alfven Waves (AW) are injected into the solar corona by imposing random, time-dependent velocity and magnetic field fluctuations at the photosphere. As these AWs propagate through the inhomogeneous background plasma, inward-propagating AWs are produced by partial reflections of the outward-propagating AWs, resulting in a vigorous MHD turbulence cascade mediated by the nonlinear interactions between counter-propagating AWs. Relevant results from the simulations and phenomenological model will be discussed in the context of existing in-situ and remote observations of the inner heliosphere. The simulations also show that when the key physical parameters are chosen within observational constraints, reflection-driven Alfven turbulence becomes a plausible mechanism for the heating and acceleration of the fast solar wind. By flying a virtual Parker Solar Probe (PSP) through the simulations, we will also explore the extent to which the turbulence properties observed in the simulations can be inferred from single-point measurements to compare with actual PSP measurements when the Taylor Hypothesis is no longer valid.