Accretion Disk Matt Coleman Institute for Advanced Study Boundary - PowerPoint PPT Presentation

Accretion Disk Matt Coleman Institute for Advanced Study Boundary Layers mcoleman@ias.edu UNLV - Athena++ User Meeting - 3/20/19

The Boundary Layer P disk, ram > P ⋆ , mag • Where the disk meets the star • MRI doesn’t work • How does angular momentum transport here work? Mach number v kep ( R ⋆ ) ℳ = ≫ 1 C s

The Boundary Layer ℳ = ( 1/8 ) G 3 σ m 4 8 π M 3/2 μ 1/2 · u M − 1/8 R − 1/8 τ − 1/8 k 4 3 b (CV hot) = 32 ( 3/8 0.6 M ⊙ ) 1/2 − 1/8 10 4 ) ( 0.6 ) ( M μ R τ · M − 9 9 Mm (CV cold) = 270 ( 3/8 0.6 M ⊙ ) 1/2 − 1/8 ( 2 ) ( 5 ) M μ R τ · M − 11 9 Mm (AM CVn hot) = 55 ( 3/8 1.1 M ⊙ ) 1/2 − 1/8 5 × 10 4 ) ( 1.4 ) ( M μ R τ · M − 9 4.7 Mm (AM CVn cold) = 330 ( 3/8 1.1 M ⊙ ) 1/2 − 1/8 ( 4 ) ( 2000 ) M μ R τ · M − 12 4.7 Mm (PPD) = 53 ( 3/8 − 1/8 75 ) M ⊙ ) ( 1/2 ( 2 ) M μ R τ · M − 8 2 R ⊙ (FU Ori) = 5.3 ( 3/8 − 1/8 M ⊙ ) ( 6 × 10 5 ) 1/2 ( 0.6 ) M μ R τ · M − 5 2 R ⊙ h ⋆ ∼ ℳ − 2 , dt ∼ h ⋆ ℳ ∼ ℳ − 3 Numeric considerations

Supersonic Shear Hydrodynamically Unstable

Possible DNO

One-armed Spiral 3/2 R ⋆ ( r p ) ϕ = ϕ 0 − sign ( r − r p ) R ⋆ R ⋆ R ⋆ r + r 2 − 3 r p

Azimuthal Wave Modes

Angular Momentum Transport m9-0.90 t/ 2 π = 299 . 9 − 399 . 9 × 10 − 5 0 C S − 1 C S = Stress Transport C S 10 5 11 16 4 sum − 2 C A = Advective Transport 1 . 0 1 . 2 1 . 4 1 . 6 1 . 8 2 . 0 2 . 2 2 . 4 C L = C S + C A = Total Transport × 10 − 4 0 . 0 − 0 . 5 C L C A C S 1 . 0 1 . 2 1 . 4 1 . 6 1 . 8 2 . 0 2 . 2 2 . 4

2D Runs Sim Class M Runs done Nr Nphi 2DM5 5 2 1024 1024 2DM6 6 4 1024 1024 2DM6HR 6 6 2048 2048 2DM7 7 1 2048 2048 2DM8 8 1 2048 2048 2DM9LR 9 7 2048 2048 2DM9 9 7 4096 4096 2DM9HR 9 1 8192 8192 2DM10 10 1 4096 4096 2DM11 11 1 4096 4096 2DM12 12 5 4096 4096 2DM13 13 1 8192 8192 2DM14 14 1 8192 8192 2DM15 15 1 8192 8192

Dispersion Relation 0 . 8 Curves are single parameter fit. 0 . 7 0 . 6 ℳ − 2 + ( 2 2 mr 0 ) Ω p ℳ R ⋆ 0 . 5 = Ω p Ω ( R ⋆ ) 0 . 4 0 . 3 M =5 , r 0 =0 . 82 M =8 , r 0 =0 . 88 0 . 2 M =6 , r 0 =0 . 85 M =9 , r 0 =0 . 89 M =7 , r 0 =0 . 86 0 . 1 5 10 15 20 25 30 m

3D Preliminary Results

3D Preliminary Results

Matt Coleman Summary Institute for Advanced Study mcoleman@ias.edu Accretion Disk Boundary Layers •Stable to MRI → •Supersonic shear AM Transport •Possible explanation of DNO •Fourer decomposition •Working on 3D