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Explore Photospheric MHD simulation of solar pores using the MURaM code to study pore evolution, magnetic fields, and energy transport. Detailed results on temperature contours, magnetic field lines, and pore topology provided.
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MSI Workshop Photospheric MHD simulation of solar pores Robert Cameron Alexander Vögler Vasily Zakharov Manfred Schüssler Max-Planck-Institut für Sonnensystemforschung Katlenburg-Lindau, Germany
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 1.4 Mm 12 Mm 12 Mm
The MURaM code University of Chicago: Basic MHD code MPS (Alexander Vögler): Radiative Transfer Hyper Diffusivities • Finite Differences • Fixed, uniformly spaced mesh (288 x 288 x 100) • Forth order in space • Runge-Kutta • Hyper Diffusivities • Short Characteristic method for radiation
Results Intensity |B| (tau=1) Bvert (tau=1) Uvert (tau=1)
Vertical Structure Pore simulation Quiet Sun Simulation Observed pores (Sutterlin) Simulations
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 log(Tau constant geometrical depth) Intensity Vertical magnetic field (Tau=1 surface)
Slice Temperature contours Temperature Tau=1 level Magnetic field lines Magnetic energy Tau=1 level
Radial Structure TAU=1 TAU=0.1
Radial Structure TAU=1 TAU=0.1
Topology From bottom to top From top to bottom Inverse U loops
Evolution Average field strength (depends on how pore is defined) Flux decay from pore
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.