1. Numerical simulation of effects of reduced excitationof 5-min.solar oscillations in sunspots Konstantin Parchevsky, Alexander Kosovichev Stanford University, HEPL

2. Motivation The amplitude of 5-min. oscillations is significantly smaller in sunspots than in the quiet Sun. The amplitude of 5-min. oscillations is significantly smaller in sunspots than in the quiet Sun. Lack of wave sources inside sunspots where convection is suppressed by strong magnetic field. Lack of wave sources inside sunspots where convection is suppressed by strong magnetic field. Interaction of incoming waves with magnetic field and perturbations of pressure and density inside sunspots. Interaction of incoming waves with magnetic field and perturbations of pressure and density inside sunspots.

4. k-  diagram simulations observations

5. Artificial mask

6. Amplitude maps observations simulations  = 3.65 ± 0.6 mHz amplitude ratio:4.0 ± 0.94.6 ± 1.0 MDI continuum 120  120  50 Mm 3

7. Amplitude ratio vs. sunspot diameter

8. Conclusion 1. The suppression of acoustic sources inside sunspots can almost entirely explain the reduced oscillation amplitude observed in sunspots. 2. Amplitude ratio of acoustic waves inside and outside sunspots depends on sunspots radii. The bigger radius, the bigger suppression.