Portal de Periódicos da CAPES

The effects of scattering on solar oscillations

1994; IOP Publishing; Volume: 424; Linguagem: Inglês

10.1086/173905

1538-4357

Peter Goldreich, Norman Murray,

Solar and Space Plasma Dynamics

view Abstract Citations (39) References (19) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Effects of Scattering on Solar Oscillations Goldreich, Peter ; Murray, Norman Abstract Acoustic modes are scattered by turbulent velocity fluctuations in the solar convection zone. The strongest scattering occurs near the top of the acoustic cavity where the mode changes character from propagating to evanescent. This layer is located at depth z1 approximately g/omega2 below the photosphere. The scattering optical depth taus is of order M12, where M1 is the Mach number of the energy-bearing eddies at z1. The corresponding contribution to the line width is gammas is approximately (omega) M12/(pi)(n+1), where n is the mode's radial order. At the top of the acoustic cavity the correlation time of energy-bearing eddies is much longer than omega-1. Also, the pressure scale height H and the eddy correlation length Lambda are comparable to omega/c, where c is the sound speed. Thus scattering couples modes of similar omega and all l and has little effect on the sum of their energies. Observations show that mode energies decline with decreasing n (increasing l) at fixed omega. Consequently, scattering damps p-modes and excites f-modes. Publication: The Astrophysical Journal Pub Date: March 1994 DOI: 10.1086/173905 Bibcode: 1994ApJ...424..480G Keywords: Acoustic Scattering; Solar Convection (Astronomy); Solar Oscillations; Turbulence; Reynolds Stress; Solar Atmosphere; Astrophysics; CONVECTION; SUN: INTERIOR; SUN: OSCILLATIONS full text sources ADS |