Vincent van Gogh s The Starry Night (1889) the view from the window of his asylum room at Saint-Rémy-de-Provence / 15

Transcription

1 ( ) Vincent van Gogh s The Starry Night (1889) the view from the window of his asylum room at Saint-Rémy-de-Provence 1 / 15

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3 Karman vortex Tropical cyclone (Hurricane, Typhoon) CEReS NICT JMA HIMAWARI Visualization Team on YouTube Wingtip vortex Ca II nm Wedemeyer-Böhm et al (Wedemeyer-Böhm & Rouppe van der Voort 2009) 3 / 15

4 MHD 2017: 磁気流体プラズマ乱流中の渦の構造とダイナミクス 加藤成晃 Solar Chromosphere Downloaded from on March 18, 2017 Spicules = Dynamical fibrils 3131 Review. Photosphere and chromosphere E Solar granules Corona G D D F F C Chromosphere Photosphere B B A Hinode/Solar Optical Telescope (SOT) A Convection Zone Figure 1. Sketch of the granulation supergranulation spicule complex in cross section. A, Flow lines of a supergranulation cell. B, Photospheric granules. C, Wave motions. D, Large-scale chromospheric flow field seen in Ha. E, [Magnetic] lines of force, pictured as uniform in the corona but concentrated at the boundaries of the supergranules in the photosphere and chromosphere. F, Base of a spicule bush or rosette, visible as a region of enhanced emission in the Ha and K-line cores. G, Spicules. [...] The distance between the bushes is km. Reproduced with permission from Noyes [15], including this caption. Rutten 2012 Hinode/Ca II H BFI movie (courtesy by Mats Carlsson) In terms of physics, the principal quiet-sun photospheric agents are gas dynamics and near-local thermodynamic equilibrium (near-lte) radiation loss outside magnetic concentrations, magnetohydrodynamics (MHD) within the latter. These processes are presently emulated well in three-dimensional timedependent simulations of photospheric fine structure. The spatial simulation extent4is /still too small to contain full-fledged active regions, but sunspots [12] 15 and supergranules [13,14] come into reach. Higher up, the radiation losses become

5 Magnetic flux tube as magnetic portal Current sheets will form at the boundary of field lines. Dissipation E Corona Propagation F G D β=pgas/pmag=1 C D Chromosphere Photosphere F Parker 1979, 1990 Magnetic reconnections B Generation τ5000=1 A Convection Zone A B YK et al Longitudinal wave Transverse wave Torsional wave Figure 1. Sketch of the granulation supergranulation spicule complex in cross section. A, Flow? lines of a supergranulation cell. B, Photospheric granules. C, Wave motions. D, Large-scale chromospheric flow field seen in Ha. E, [Magnetic] lines of force, pictured as uniform in the corona but concentrated at the boundaries of the supergranules in the photosphere and chromosphere. F, Base of a spicule bush or rosette, visible as a region of enhanced emission in the Ha and K-line cores. G, Spicules. [...] The distance between the bushes is km. Reproduced with permission from Noyes [15], including this caption. Rutten 2012 Pumping Buffeting Swirling 5 / 15

6 How to find a vortex? Streamlines Vorticity magnitude Local pressure minimum vorticity Rest frame Slow co-moving frame Fast co-moving frame D0 = 2000 km y [Mm] (b) r v =! a shear flow y [Mm] (e) YK & Wedemeyer x [Mm] 6 / 15

7 Recent measures of a vortex by an imaginary part of eigenvalue of the velocity gradient tensor Swirling Strength = (Moll et al. 2011) dv dr = N D The singular point analysis/classification on the differential equations jected on a two-dimensional view plane. Consider the velocity gradient tensor, D ij D ij j (2) If are the eigenvalues of D ij, then h Dij I i e = 0 (3) Two real roots with opposite sign Pure imaginary roots r Two real roots with same sign Complex roots where e is the eigenvector. The eigenvalues can be determined by solving the characteristic equation det h D ij I i = 0 (4) which, for a velocity flow in two-dimensional space v = (v x, v y ), can be written as 2 + P + Q = 0 (5) where P = tr(d ij ) and Q = det (D ij ). Equation (5) has the following canonical solutions: = P ± p P 2 4Q. (6) 2 7 / 15

8 Testing a new detection algorithm YK & Wedemeyer 2017 A&A A new 3D numerical simulation by using CO 5 BOLD CO 5 BOLD (Freytag et al. 2008) Fortran90+OpenMP MHD: HLLC solver with the Janhunen source terms. Long-characteristic Radiation Transfer Equations of State assuming LTE The velocity field at z=1 Mm is used as an input for testing the detection algorithm Initial model (similar to Wedemeyer-Böhm et al. 2012, Nature) B0 = 50G (strictly vertical) Horizontal extent: 8.0 Mm x 8.0 Mm (11 x 11 ) Vertical extent: -2.4 Mm to +2.4 Mm x=28 km in horizontal direction (286 3 meshes) Velocity field at z=1 Mm 8 / 15

9 YK & Wedemeyer 2017 A&A 9 / 15

10 YK & Wedemeyer 2017 A&A 4000 E 2000 y [km] km 400 km B F G D C D F B 1000 km A A x [km] Figure 1. Sketch of the granulation supergranulation spicule complex in cross section. A, Flow lines of a supergranulation cell. B, Photospheric granules. C, Wave motions. D, Large-scale chromospheric flow field seen in Ha. E, [Magnetic] lines of force, pictured as uniform in the corona but concentrated at the boundaries of the supergranules in the photosphere and chromosphere. F, Base of a spicule bush or rosette, visible as a region of enhanced emission in the Ha and K-line cores. G, Spicules. [...] The distance between the bushes is km. Reproduced with permission from Noyes [15], including this caption. Rutten / 15

11 YK & Wedemeyer 2017 A&A Wedemeyer-Böhm & Rouppe van der Voort 2009 Enhanced vorticity Vorticity strength Wedemeyer-Bohm et al Wedemeyer-Bohm et al Enhanced vorticity 11 Vorticity strength 100 Histogram of events 10 Histogram of events Diameter [Mm] (a) Lifetime [min] 20 (b) Diameter [Mm] (c) Lifetime [min] / 15

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13 Toward Simulation of Protoplanetary Disk interstellar magnetic field Jet and outflows flares Wind central star UV & X-ray photons stellar magnetic field Photoionized MRI inactive MRI active CANS+ Ionized by viscous heating r A r I r in r out Inner Turbulent Region Quiescent region Outer Turbulent Region Magnetohydrodynamic Simulation Code CANS+: Assessments and Applications Yosuke MATSUMOTO 1,2,YutaASAHINA 3,YukiKUDOH 1,Tomohisa KAWASHIMA 3,4,JinMATSUMOTO 5,HiroyukiR.TAKAHASHI 3,Takashi MINOSHIMA 6,SeijiZENITANI 4,TakahiroMIYOSHI 7,andRyojiMATSUMOTO 1 13 / 15

14 Revisiting simulations of magnetic tower jet β=10 β=100 low high Ambient pressure 14 / 15

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16 α 16 / 15