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Wave driven non‐linear flow oscillator for the 22‐year solar cycle
Author(s) -
Mayr Hans G.,
Wolff Charles L.,
Hartle Richard E.
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2000gl012223
Subject(s) - oscillation (cell signaling) , physics , zonal flow (plasma) , mechanics , geophysics , kelvin wave , quasi biennial oscillation , convection , turbulence , solar cycle , gravity wave , flow (mathematics) , buoyancy , reversing , amplitude , momentum (technical analysis) , magnetic field , meteorology , gravitational wave , troposphere , solar wind , astrophysics , plasma , optics , tokamak , materials science , finance , economics , composite material , biology , genetics , quantum mechanics
In the Earth's atmosphere, a zonal flow oscillation is observed with periods between 20 and 32 months, the Quasi Biennial Oscillation. This oscillation does not require an external time dependent source but is maintained by non‐linear wave momentum forcing. We propose that such a mechanism also drives long‐period oscillations in planetary and stellar interiors, and we apply it here to generate a flow oscillation for the 22‐year solar cycle. The oscillation would occur just below the convective envelope—in a region where gravity waves can propagate. We present results from a simplified analytical model that incorporates Hines' gravity wave parameterization. Wave amplitudes <10 m/s can produce reversing zonal flows of 20 m/s that should be sufficient to generate a corresponding oscillation in the poloidal magnetic field. The low buoyancy frequency and associated increase in turbulence help produce the desired oscillation period of the flow and should help generate the currents for the reversing magnetic field.