From detailed magneto-convection simulations to modelling the

convection zone-corona system

Mats CarlssonInstitute of Theoretical Astrophysics,

University of OsloMonterey February 14 2006

Detailed simulations of magnetoconvection

•Optimization of observables

•Calibration of observables

•Interpretation

•Current status

•Future prospects

Simulations of convection zone - corona

•Nordlund/Stein code

•multi-group opacities, 4 bins

•Initial field 250G, vertical, single polarity

•253x253x163 simulation

•RT each snapshot, 2728 frequency points

•Line blanketing: 845 lines

MHD simulation of Solar magneto-convection

G-band spectral region

Solar atlasSimulation

G-band synthetic image

Comparison with observations

Simulation, mu=0.6Observation, mu=0.63

Vertical velocity

Line wingLine center

Velocity response function

Spectrum from simulation

Smeared with telescope+atm PSF

Observations

Velocity determination

Modelling coronal heating

•Magnetic field from MDI•Potential field extrapolation

•Footpoint motion statistically described•Conduction and thin losses included•Chromosphere with artificial heating/cooling function

Gudiksen & Nordlund 2005

Piecing it all together

•16x8x12 Mm (2 Mm below, 10 Mm above)

•Open boundaries

•Multi-group opacities (4 bins) with scattering

•Conduction along field-lines

•Optically thin losses in corona

•Various initial magnetic field configurations

Hansteen 2004

3D model from convection zone to corona

2D version

QuickTime™ and aGIF decompressor

are needed to see this picture.

nx=128, dx=130 km

2D version

QuickTime™ and aGIF decompressor

are needed to see this picture.

nx=512, dx= 32 km

Future modelling

•Convection zone

•multi-group opacities

•selected opacity sampling

•Magnetoconvection

•20 km resolution, 6 Mm x 6 Mm 300x300

•Supergranulation

•48 Mm x 48 Mm, 50 km resolution 1000x1000

Future modelling•Chromosphere

•Scattering

•approximate cooling in H, CaII, MgII

•time dependent H-ionization (implicit)

•CO chemistry (implicit)

•Corona

•Conduction along field lines (implicit)

Future modelling

•3D Radiation MHD simulations from convection zone to corona necessary but also within reach

•Methodology known

•Several groups active

•Future of chromospheric modelling is promising!