Radiative MHD - MPIA.dekuiper/talks/R_KUIPER... · Figure II.1: Logarithmic plasma beta for...

November, 04. 2008Rolf Kuiper IAUS 259, Tenerife

Radiative MHD with Makemake Application I: Massive Star Formation Application II: Accretion Disks Contact

Radiative MHD Radiative MHD in Massive Star Formation and Accretion Disksin Massive Star Formation and Accretion Disks

Rolf Kuiper, Hubert Klahr, Mario Flock, Henrik Beuther, Thomas Henning

IAUS 259, Tenerife, November, 04. 2008



Radiative MHD with “Makemake” and “Pluto”:We developed a fast 3D frequency-dependent radiation transport module, called Makemake [7],

and implemented it successfully with the freely available MHD-code Pluto [6].

Features of Makemake:

Geometries: Cartesian, Cylindrical and Spherical coordinates in 1,2 and 3D.

Gray (opacity-averaged) Flux-Limited Diffusion approximation

+ Frequency-dependent Irradiation (1st order Ray-tracing).

MPI-parallelized modern GMRES-solver using the PETSc-library [3].

Performance of Makemake:

CPU-time comparable or even faster than hydro step (compared with an accretion disk setup

in Pluto).

Parallel speedup higher than hydro-solver.

Accuracy for a single object source (setup adopted from the Pascucci Radiation Benchmark

Test [4]) comparable to full frequency-dependent Monte-Carlo radiative transfer method

(but incredible faster than MC!).

References: [4] I. Pascucci et al. 2004[1] R. Kuiper, H. Klahr, C.P. Dullemond, in prep. [5] C.P. Dullemond et al. 2004[2] H. Klahr, C.P. Dullemond, W. Kley, R. Kuiper, in prep. [6] A. Mignone 2007[3] S. Balay et al. 2001, PETSc web page [7] R. Kuiper, www.mpia.de/~kuiper → Research

http://www.mpia.de/~kuiper



Radiative MHD with “Makemake” and “Pluto”:We developed a module for fast 3D frequency-dependent radiat

d combined it successfully with the freely available MHD code Pluto [6].

Features of Makemake:

Gal and Spherical coordinates in 1,2 and 3D (stretched in x).

Gray (opacity-averaged) Flux-Limited Diffusion approximation

+ Frequency-dependent Irradiation (1st order Ray-tracing).

MPI-parallelized modern GMRES-solver using the PETSc-library [3].

Ce comparable or even faster than hydro step (com

pared with an accretion disk setup in Pluto).

Parallel efficiency higher than hydro-solver.

Accuracy for a single object source (setup adopted from the Pascucci Radiation Benchmark

Test [4]) comparable to full frequency-dependent Monte-Carlo radiative transfer method

(but incredible faster than MC!).

This setup was adopted from [4].For additional tests and more details see [1] and [2].

x [AU]

T [K]

[°]

Polar cut at r = 2 AU

intermediate layer

y [AU]

x [AU]

y [AU] log T

90

260

200

Dots: RADMCDashed line: 'our' RT

The turnover point from optical thin to optical thick regions is reproduced!

-90

x [AU]=100 :

(T-TMC

) / TMC

) [%](T-TMC

) / TMC

) [%]

Radial cut through

midplane

r [AU]

T [K]340

01 1000

10001-15

-10

-5

Dots: RADMCDashed line: 'our' RT

The deviations from the Monte-Carlo method stays below 15% (same order as for different MC codes)!

-90

Results of the comparison of Makemake with the Monte-Carlo based radiative transfer code RADMC [5].

References: [4] I. Pascucci et al. 2004[1] R. Kuiper, H. Klahr, C.P. Dullemond, in prep. [5] C.P. Dullemond et al. 2004[2] H. Klahr, C.P. Dullemond, W. Kley, R. Kuiper, in prep. [6] A. Mignone 2007[3] S. Balay et al. 2001, PETSc web page [7] R. Kuiper, www.mpia.de/~kuiper → Research




Setup (adopted from Yorke & Sonnhalter 2002):

Massive core with outer Radius = 0.1pc.

Total Mass = 60 Msol

.

Density drops with r-2.

Temperature = 20 K.

Initial Angular Momentum = 0 (1D) or 5*10-13 Hz (2D).

Included Physics (in different runs):

Isothermal.

Adiabatic.

Diffuse cooling (infrared dust emission).

Irradiation feedback from central star.

Radiation pressure feedback from central star.

Frequency-dependent irradiation and radiation pressure.

Application I: Massive Star Formation



Results 1D:

Frequency-dependent radiation pressure limits the final stellar mass to ~30Msol

(~50% Mtot

).

Time [1000 years]

Mstar

[Msol

]

Frequency-dependent Radiation Pressure

Isothermal




Results 2D:

Due to angular momentum conservation the

adiabatic collapse forms a several 100 AU

torus as well as polar cavities.

The prior free-fall era leads to a 10 Msol

star.

Further accretion is only possible via

gravitational, radiative or magnetic instabilities.

Cloud (0.1pc)

Inner region

Both panels:Left color = Radial Velocity

(blue Infall, red Outflow)Left contour = Density (log)Right color = Density (log)Right contour = Temperature (log)




Next steps:

Frequency-dependent 2D runs.

3D simulations of Graviational Instabilities in the

resulting disk/torus.

3D simulations of developing MRI in the resulting disk.

See also “Application II”.

Application I: Massive Star FormationCloud (0.1pc)

Inner region

Both panels:Left color = Radial Velocity

(blue Infall, red Outflow)Left contour = Density (log)Right color = Density (log)Right contour = Temperature (log)



Application II: MRI in accretion disksSetup:

Proto-planetary disk in hydrostatic equilibrium.

Toroidal magnetic field with constant plasma beta about 25.

A small random velocity seed drives to MRI.

Radial boundary: Perfect conductive plate.

Vertical and azimuthal boundary: Periodic.

Code and configuration:

Pluto 3.0 with

Second order Godunov scheme (hlld)

Upwind constraint transport (ct) - Consistent electromotive force reconstruction (emf)



Application II: MRI in accretion disksResults:

Within the first 100 inner orbits a highly magnetized corona is forming (plasma beta < 1),

while the midplane of the disk remains at large plasma beta values susceptible for the MRI

(see azimuthal averaged plasma beta in Figure II.1).

Figure II.1: Logarithmic plasma beta for 100x25x25 (left) , 200x50x50 (middle) and 400x100x100 (right) after 10 orbits (at 5 [AU]) in turbulent state.



Application II: MRI in accretion disks


Figure II.2: Maxwell-Stress evolution for three diff. Resolutions. The values converge against each other.

Results:

Within the first 100 inner orbits a highly magnetized corona is forming (plasma beta < 1),

while the midplane of the disk remains at large plasma beta values susceptible for the MRI

(see azimuthal averaged plasma beta in Figure II.1).

For all studied resolutions the turbulence converges against an alpha value about 0.01 (see

Figure II.2).



Application II: MRI in accretion disksNext steps:

First MRI-runs including Makemake radiative transfer are currently performed on our cluster.

Non-Ideal Radiative MHD with temperature-dependent dynamical resistivity.


Figure II.2: Maxwell-Stress evolution for three diff. Resolutions. The values converge against each other.



Interested?For more details about our projects, access to our code, hints or remarks of any kind:

Visit www.mpia.de/~kuiper → Research → Radiative Transfer for MHD.

Mail to [email protected].

Ask me during these days!


mailto:[email protected]



Interested?For more details about our projects, access to our code, hints or remarks of any kind:

Visit www.mpia.de/~kuiper → Research → Radiative Transfer for MHD.

Mail to [email protected].

Ask me during these days!

Thanks for your attentionand

enjoy your stay!


mailto:[email protected]

Radiative MHD - MPIA.dekuiper/talks/R_KUIPER... · Figure II.1: Logarithmic plasma beta for...

Documents

Transcript of Radiative MHD - MPIA.dekuiper/talks/R_KUIPER... · Figure II.1: Logarithmic plasma beta for...