[mesa-users] Zero Brunt-Vaisala freq. in outer regions of GYRE output files

[Josiah Schwab]

On 10 June 2014 at 12:13 PDT, Richard Townsend wrote:
> Looking at these models, it appears that the BV frequency is
> identically zero in the outer ~40 zones (example attached — see column
> 9 for N^2). Has anyone else encountered this — and is there a fix?

You have add_atmosphere_to_pulse_info = .true. and the brunt is not
calculated in the atmosphere.

See star/private/pulsation_info.f

,----
| subroutine store1_gyre_point(j)
|    integer, intent(in) :: j
|    integer :: k, i
|
|    include 'formats'
|    
|    i = nn - j + 1
|    if (j < atm_pts) then ! in atmosphere
|    
|       k = atm_pts-j+1 ! k is index of point in atm_structure
|          ! we skip the point at the base of the atm to smooth the transition
|
|       r(i) = s% r(1) + s% atm_structure(atm_delta_r,k)
|       w(i) = 1d99
|       L(i) = s% L(1)
|       p(i) = exp_cr(s% atm_structure(atm_lnP,k))
|       rho(i) = exp_cr(s% atm_structure(atm_lnd,k))
|       T(i) = exp_cr(s% atm_structure(atm_lnT,k))
| >>>   N2(i) = 0d0
|       Gamma_1(i) = s% atm_structure(atm_gamma1,k)
|       nabla_ad(i) = s% atm_structure(atm_grada,k)
|       delta(i) = s% atm_structure(atm_chiT,k)/s% atm_structure(atm_chiRho,k)
|       nabla(i) = s% atm_structure(atm_gradT,k)
|       kappa(i) = s% atm_structure(atm_kap,k)
|       kappa_rho(i) = kappa(i)*s% atm_structure(atm_dlnkap_dlnd,k)
|       kappa_T(i) = kappa(i)*s% atm_structure(atm_dlnkap_dlnT,k)
|       epsilon(i) = 0d0
|       epsilon_rho(i) = 0d0
|       epsilon_T(i) = 0d0
|       if (s% rotation_flag) then
|          omega(i) = s% omega(1)
|       else
|          omega(i) = 0d0
|       end if
|       
|       if (p(i) >= P_prev) then
|          write(*,2) 'WARNING: atmosphere P >= P_prev', k, p(i), P_prev
|          write(*,'(a)') ' try decreasing create_atm_max_step_size to get more atm points'
|       end if
|       
|    else ! j > atm_pts
|
|    ...
|
| end subroutine store1_gyre_point
`----

Josiah