The SWIM “Slow” MHD Campaign: Overview, MHD Plans and Accomplishments
Photospheric MHD simulation of solar pores
description
Transcript of Photospheric MHD simulation of solar pores
Photospheric MHD simulation of solar pores
Robert CameronAlexander VöglerVasily Zakharov
Manfred Schüssler
Max-Planck-Institut für Sonnensystemforschung Katlenburg-Lindau, Germany
MSI Workshop
Equations
• Compressible non-ideal MHD with radiation
– Momentum equation, Lorentz force and artificial viscosity
– Continuity equation– Induction equation, with proper diffusion– Energy equation, with non-gray radiation– Equation of state, including partial ionization
Setup
• Box size 288 x 288 x 100 grid points
• Boundary conditions Vertical field above box OR Potential field above box
• Initial Conditions Two total fluxes considered (today only larger case considered). Simulate 2-D to get near equilibrium then create 3-D initial condition. Injection of some opposite polarity flux in some runs
12 Mm 12 Mm1.4
Mm
The MURaM code
• Finite Differences• Fixed, uniformly spaced mesh (288 x 288 x 100)• Forth order in space• Runge-Kutta• Hyper Diffusivities
• Short Characteristic method for radiation
University of Chicago: Basic MHD codeMPS (Alexander Vögler): Radiative Transfer
Hyper Diffusivities
Results
Intensity|B| (tau=1)
Bvert (tau=1) Uvert (tau=1)
Vertical StructureP
ore
sim
ulat
ion
Qui
et S
un S
imul
atio
nO
bser
ved
pore
s (S
utte
rlin)
Sim
ulat
ions
Vertical Structure 2: Energy transport
Temperature Vertical Field
Z=-240
Z=-360
Z=-480
Vertical Structure 2: Energy transport
Temperature at a fixed geometrical height (3 copies)
Vertical Structure 2: Energy transport
Intensitylog(Tau constant geometrical depth)
Vertical magnetic field (Tau=1 surface)
Intensity Tau=1,Tau=0.1
Reference frame
Slice
Magnetic field linesMagnetic energyTau=1 level
Temperature contoursTemperatureTau=1 level
Radial Structure
TAU=1
TAU=0.1
Radial Structure
TAU=1
TAU=0.1
Topology
From bottom to topFrom top to bottomInverse U loops
Evolution
Flux decay from pore Average field strength(depends on how pore is defined)
Evolution
Intensity v size
A view from the side
500nm
=0.7 0.5 0.2
Main conclusions
• Thermal properties of pore similar to observations• Magnetic fields and magnetic field gradient sensitive to
definition of the pores edge. • Energy transport involves plumes which are dark at
surface (?)• Topology is becoming interesting (but the pore is still
small).• Side views have reasonable enhancements, but is quite
smooth.