[mesa-users] Meaning of f_2 and D_2 parameters (RICHARD H D TOWNSEND)

Umberto Battino umberto.battino at unibas.ch
Mon Apr 4 11:03:10 EDT 2016

Hello Richard,

I've recently submitted a paper where I test the f_2 and D_2 parameters in low-mass AGB evolution. In this paper I want to describe the Convective-Boundary Mixing (CBM) processes in AGB accounting to Internal Gravity Waves (IGW) effect in addition to the classic convective overshooting (see Herwig 2000). Therefore, I need a parametrization able to account to 2 distinct processes.

See the attached plot for a schematic description of how those parameters act:

The red line is the standard overshooting mixing coe?fficient pro?file following the single-exponential decay. This profi?le is dominated by a single 'f1' parameter which determines the slope of the mixing profi?le: the lower the 'f1' value, the steeper the pro?file is. In order to take into account IGW, in this work I apply a second, slower, decreasing pro?file (green line) that becomes more relevant than the ?first one as soon as the mixing coe?fficient is equal or lower that a 'D2' value, the slope of which is determined by the 'f2' parameter.

Hoping this helps!



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