!-----------------------------------------------------------------------------------------------------------------------------------
! This file is part of ReMKiT1D.
!
! ReMKiT1D is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as
! published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
!
! ReMKiT1D is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
!
! You should have received a copy of the GNU General Public License along with ReMKiT1D. If not, see <https://www.gnu.org/licenses/>.
!
! Copyright 2023 United Kingdom Atomic Energy Authority (stefan.mijin@ukaea.uk)
!-----------------------------------------------------------------------------------------------------------------------------------
module janev_fits
!! author: Stefan Mijin
!!
!! Contains interfaces to fit functions from Janev's EIRENE report: http://www.eirene.de/report_4105.pdf
use data_kinds ,only: rk, ik
use physical_constants
use support_functions ,only: expInt1
implicit none
!-----------------------------------------------------------------------------------------------------------------------------------
interface
!-----------------------------------------------------------------------------------------------------------------------------------
pure module function radRecombRateHydrogen(temp,n) result(rate)
!! Radiative recombination rate given by formulas (21) and (22) from Janev Section 2.1.4. The recombination for n=2 is obtained
!! by a simple sum over the two l states. Result in 10^-14 cm^3/s
real(rk) ,dimension(:) ,intent(in) :: temp !! Temperature array in eV
integer(ik) ,intent(in) :: n !! Final atomic state after recombination
real(rk) ,allocatable ,dimension(:) :: rate
end function radRecombRateHydrogen
!-----------------------------------------------------------------------------------------------------------------------------------
pure module function excitationCrossSectionHydrogen(eGrid,n,m) result(cs)
!! Calculates hydrogen electron impact excitation cross-section from state n to state m on given energy grid.
!! NOTE: The returned value is in 10^-16 cm^2!
real(rk) ,dimension(:) ,intent(in) :: eGrid !! Electron energy grid in eV
integer(ik) ,intent(in) :: n !! Initial atomic state
integer(ik) ,intent(in) :: m !! Final atomic state
real(rk) ,allocatable ,dimension(:) :: cs
end function excitationCrossSectionHydrogen
!-----------------------------------------------------------------------------------------------------------------------------------
pure module function ionizationCrossSectionHydrogen(eGrid,n) result(cs)
!! Calculates hydrogen electron impact ionization cross-section from state n on given energy grid.
!! NOTE: The returned value is in 10^-16 cm^2!
real(rk) ,dimension(:) ,intent(in) :: eGrid !! Electron energy grid in eV
integer(ik) ,intent(in) :: n !! Initial atomic state
real(rk) ,allocatable ,dimension(:) :: cs
end function ionizationCrossSectionHydrogen
!-----------------------------------------------------------------------------------------------------------------------------------
end interface
!-----------------------------------------------------------------------------------------------------------------------------------
end module janev_fits
!-----------------------------------------------------------------------------------------------------------------------------------
