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 ρ 1 , p 1 , T 1 ρ 2 , p 2 , T 2 ρ 0 , p 0 , T 0 z y x 0 x − x 0 Uniform magnetic field in the slab. Field-free plasma outside. Different density and pressure on each side.

Asymmetric slab modes

Asymmetric slab modes

Asymmetric slab modes

Amplitude ratio v x ( − x 0 ) ˆ v x ( x 0 ) ˆ x x 0 − x 0 Amplitude ratio R A := ˆ v x ( x 0 ) ( Bottom = quasi-sausage ) Top = quasi-kink v x ( − x 0 ) ˆ ( k 2 v A 2 − ω 2 ) m 1 ρ 1 − ω 2 m 0 ρ 0 � tanh � ( m 0 x 0 ) � ρ 1 m 2 coth � + = � tanh � ρ 2 m 1 ( k 2 v A 2 − ω 2 ) m 2 ρ 0 ρ 2 − ω 2 m 0 ( m 0 x 0 ) − coth

Solar magneto-seismology Parameter inversion Observe : ω , k , x 0 , T i , and R A . Solve to find: v A and hence magnetic field strength.

”a day without the Sun is, you know, night” matthew allcock