Date : 5/18 (Wed) [15:00 - 17:00] @ F313
Speaker: Mr. Tomohiro Ono (Kyoto University)
Title : Critical Condition and Physical Mechanism of The Rossby Wave Instability
Abstract:
Protoplanetary disks with non-axisymmetric structures have b
een observed. It is often considered that the non-axisymmetr
ic structures are formed by the Rossby wave instability (RWI
). The RWI is a non-axisymmetric hydrodynamic instability in
differentially rotating disks. It is known that the RWI is
unstable and forms large-scale vortexes when the disk has a
rapid radial variation. However, the critical condition and
the physical mechanism of the RWI have not been investigated
well. We perform linear stability analyses to explore them.
As a result, we find that the co-rotation radius is located
at the background vortensity minimum with large concavity i
f the system is marginally stable to the RWI, and this allow
s us to easily check the stability against the RWI. By using
the Sommerfeld-Wilson quantization condition, which is know
n well in quantum mechanics, we newly derive the necessary a
nd sufficient condition for the onset of the RWI in semi-ana
lytic form. We also realize that the RWI is one of the shear
instabilities, and explain the physical mechanism of the RW
I by the wave interaction. In my talk, I will report these r
esults about the RWI. More detailed information is provided
in our new paper (Ono et al. in press; http://arxiv.org/abs/
1603.09225).


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