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Magneto-acoustic waves in an asymmetric magnetic slab Progress in - - PowerPoint PPT Presentation
Magneto-acoustic waves in an asymmetric magnetic slab Progress in - - PowerPoint PPT Presentation
Magneto-acoustic waves in an asymmetric magnetic slab Progress in spatial magneto-seismology Matthew Allcock and Robertus Erd elyi Motivation Equilibrium conditions 1 , p 1 , T 1 2 , p 2 , T 2 0 , p 0 , T 0 z y x 0 x x 0
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Equilibrium conditions
−x0 x0 x z y
ρ1, p1, T1 ρ0, p0, T0 ρ2, p2, T2
Uniform magnetic field in the slab. Field-free plasma outside. Different density and pressure on each side.
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Asymmetric slab modes
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Asymmetric slab modes
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Asymmetric slab modes
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Amplitude ratio
ˆ vx(−x0) ˆ vx(x0)
−x0 x0 x
Amplitude ratio
RA := ˆ vx(x0) ˆ vx(−x0) (
Top = quasi-kink Bottom = quasi-sausage)
= +
−
ρ1m2 ρ2m1 (k2vA2 − ω2)m1
ρ0 ρ1 − ω2m0
tanh
coth
- (m0x0)
(k2vA2 − ω2)m2
ρ0 ρ2 − ω2m0
tanh
coth
- (m0x0)
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Solar magneto-seismology
Parameter inversion
Observe: ω, k, x0, Ti, and RA. Solve to find: vA and hence magnetic field strength.
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