iondrv Subroutine

public subroutine iondrv(aaion, bmax, dpp, dtheta, edrive, emitt, etai, lf, nbeams, qion, sigma, sigma0, tauf, theta, vi, gain, etadrv)

Uses

Routine to calculate parameters of a heavy ion driver suitable for inertial fusion energy author: P J Knight, CCFE, Culham Science Centre aaion : input real : Ion mass (amu) bmax : input real : Maximum field at the superconductor (T) dpp : input real : Beam momentum spread dtheta : input real : Pointing error (rad) edrive : input real : Driver energy (J) emitt : input real : Normalised beam emittance (metre-rad) etai : input real : Axial quadrupole packing fraction at injection lf : input real : Distance from final focussing quad to target (m) nbeams : input integer : Number of beams qion : input real : Ion charge state sigma : input real : Depressed tune (incl. space charge effects) (deg) sigma0 : input real : Phase advance per lattice period (tune) (deg) tauf : input real : Post-acceleration pulse duration (s) theta : input real : Final focussing half angle (rad) vi : input real : Injection voltage (V) gain : output real : Target gain etadrv : output real : Driver efficiency This routine calculates the parameters of a heavy ion driver suitable for inertial fusion energy.

Currently, the complicated model taken from the reference is not complete, so it is recommended that the simple model is used (set ISIMP=1) Heavy-ion Driver Design and Scaling, R. Bieri et al., Fusion Technology, vol.21 (1992) 1583 Meier and Bieri, Fusion Technology, vol.21 (1992) 1547

Arguments

Type IntentOptional AttributesName
real(kind=dp), intent(in) :: aaion
real(kind=dp), intent(in) :: bmax
real(kind=dp), intent(in) :: dpp
real(kind=dp), intent(in) :: dtheta
real(kind=dp), intent(in) :: edrive
real(kind=dp), intent(in) :: emitt
real(kind=dp), intent(in) :: etai
real(kind=dp), intent(in) :: lf
integer, intent(in) :: nbeams
real(kind=dp), intent(in) :: qion
real(kind=dp), intent(in) :: sigma
real(kind=dp), intent(in) :: sigma0
real(kind=dp), intent(in) :: tauf
real(kind=dp), intent(in) :: theta
real(kind=dp), intent(in) :: vi
real(kind=dp), intent(out) :: gain
real(kind=dp), intent(out) :: etadrv

Contents

Source Code


Source Code

  subroutine iondrv(aaion,bmax,dpp,dtheta,edrive,emitt,etai,lf, &
       nbeams,qion,sigma,sigma0,tauf,theta,vi,gain,etadrv)

    !! Routine to calculate parameters of a heavy ion driver
    !! suitable for inertial fusion energy
    !! author: P J Knight, CCFE, Culham Science Centre
    !! aaion  : input real : Ion mass (amu)
    !! bmax   : input real : Maximum field at the superconductor (T)
    !! dpp    : input real : Beam momentum spread
    !! dtheta : input real : Pointing error (rad)
    !! edrive : input real : Driver energy (J)
    !! emitt  : input real : Normalised beam emittance (metre-rad)
    !! etai   : input real : Axial quadrupole packing fraction at injection
    !! lf     : input real : Distance from final focussing quad to target (m)
    !! nbeams : input integer : Number of beams
    !! qion   : input real : Ion charge state
    !! sigma  : input real : Depressed tune (incl. space charge effects) (deg)
    !! sigma0 : input real : Phase advance per lattice period (tune) (deg)
    !! tauf   : input real : Post-acceleration pulse duration (s)
    !! theta  : input real : Final focussing half angle (rad)
    !! vi     : input real : Injection voltage (V)
    !! gain   : output real : Target gain
    !! etadrv : output real : Driver efficiency
    !! This routine calculates the parameters of a heavy ion driver
    !! suitable for inertial fusion energy.
    !! <P>Currently, the complicated model taken from the reference is not
    !! complete, so it is recommended that the simple model is used
    !! (set <CODE>ISIMP=1</CODE>)
    !! Heavy-ion Driver Design and Scaling, R. Bieri et al.,
    !! Fusion Technology, vol.21 (1992) 1583
    !! Meier and Bieri, Fusion Technology, vol.21 (1992) 1547
    !!
    ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

    use constants, only: echarge, mproton, degrad, pi
    implicit none

    !  Arguments

    real(dp), intent(in) :: aaion,bmax,dpp,dtheta,edrive,emitt,etai,lf,qion, &
         sigma,sigma0,tauf,theta,vi
    integer, intent(in) :: nbeams
    real(dp), intent(out) :: gain,etadrv

    !  Local variables

    real(dp), parameter :: c2 = 8.98755178737D16
    integer, parameter :: isimp = 1  !  Switch for simple model (1=yes)

    real(dp) :: ci,de,dgap,dlcore,drcore,e,eomc2,fins,floss, &
         ibf,ibfo,ibi,ibpc,lfocus,lpf,lpfo,lpi,lppc,lq,phif,phifo, &
         phii,phipc,rion,rs,rs1,rs2,rs3,rs4,sig,sig0,taufo,taui, &
         taupc,tbrad,vf,vfo,vpc,vs,vscore,vshe,vsle,vspc,xhe,xle,xpc
    real(dp), dimension(10) :: eve,gve
    integer :: i,ie,j,nche,ncle,ncpc,nqarrs,nqle,nqpche,nquads

    ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

    if (isimp /= 1) then

       !  Complex IONDRV model (incomplete)...
       !  ====================

       !  Electron charge / (proton mass * c**2)

       eomc2 = echarge / (mproton*c2)

       !  Degrees to radians

       sig = sigma * degrad
       sig0 = sigma0 * degrad

       !  Beam current coefficient

       ci = cbeam(etai,bmax,aaion,qion,sig,sig0,emitt,vi,eomc2)

       !  Final voltage (V)

       vf = (edrive/(dble(nbeams)*tauf*ci))**(0.666666D0)

       !  Final beam current (A)

       ibf = ci*sqrt(vf)

       !  Ion range (g/cm^2)

       rion = (3.04D-5 * aaion + 349.0D0*aaion**(-2.21D0)) * &
            (qion*vf/1.0D9)**(1.72D0-0.00275D0*aaion)

       !  Convert to kg/m^2

       rion = rion*10.0D0

       !  Total spot size (rms of four terms):
       !  (1) Emittance term

       rs1 = emitt / (betgam(aaion,qion,vf)*theta)

       !  (2) Dispersion (momentum spread) term

       rs2 = 8.0D0*dpp*lf*theta

       !  (3) Alignment and jitter term

       rs3 = dtheta*lf

       !  (4) Space charge term (inaccurate at present)

       rs4 = 1.0D-3

       rs = sqrt(rs1**2 + rs2**2 + rs3**2 + rs4**2)

       !  Target gain (inaccurate at present)

       gain = 62.6D0 - 142.3D0*rs**1.25D0 * rion**0.633D0 + &
            (32.8D0+82.1D0*rs)**0.783D0 * rion**0.647D0 * &
            log(1.0D-6*edrive)

       !  Source/Injector characteristics:
       !  Transport beam radius (m)

       tbrad = ( (emitt**2 * sig0 * c2)/(sig**2 * bmax/1.5D0 * etai * &
            sqrt(vi)) )**(0.333333D0) * sqrt(2.0D0 * aaion * mproton / &
            (qion * echarge))

       !  Extractor voltage (V)

       vs = 4.0D0/3.0D0 * vi

       !  Source extraction gap width (m)

       dgap = 0.8D0

       !  Injected current per beam (A)

       ibi = 4.0D0 * pi * tbrad**2 * 5.46D-8 * &
            sqrt( qion*vs**3/(aaion*dgap**4) )

       !  Beam loss fraction between injector and target

       floss = 0.08D0

       !  Pulse duration at injection (s)

       taui = 1.0D0/(1.0D0-floss) * tauf * ibf / ibi

       !  Pulse length at injection (m)

       lpi = taui * sqrt( 2.0D0 * qion * echarge * vi / (aaion * mproton) )

       !  Initial voltage gradient (V/m)

       phii = 0.3D0 * vi / lpi

       !  End of Low Energy Transport Stage:
       !  Insulated fraction of driver length

       fins = 0.85D0

       !  Maximum voltage gradient, limited by insulator flash-over (V/m)

       phifo = 1.0D6 * fins

       !  Voltage at which this limit is reached (V)
       !  The end of the low energy stage is set by the point at which
       !  the limit is reached.

       vfo = (phifo/phii)**(2.0D0/3.0D0) * vi

       !  Beam current (A)

       ibfo = ibi * (vfo/vi)

       !  Pulse duration (s)

       taufo = taui * (vi/vfo)

       !  Pulse length (m)

       lpfo = taui * vi / vfo * sqrt( 2.0D0 * qion * echarge * vfo / &
            (aaion * mproton) )

       !  Length of the low energy transport stage (m)
       !  (rearrangement of integral of PHI(V).dl)

       xle = 2.0D0*vi**1.5D0 / phii * (1.0D0/sqrt(vi) - 1.0D0/sqrt(vfo))

       !  End of Pulse Compression Stage:
       !  Pulse length = final pulse length (m)

       lpf = tauf * sqrt( 2.0D0 * qion * echarge * vf / (aaion * mproton) )
       lppc = lpf

       !  Length of the pulse compression region (m)

       xpc = (lpfo - lpf)/0.3D0

       !  Voltage gradient (V/m) - limit already reached

       phipc = phifo

       !  Voltage (V)

       vpc = vfo + (xpc*phipc)

       !  Beam current (A)

       ibpc = ibfo * (lpfo/lppc) * sqrt(vpc/vfo)

       !  Pulse duration (s)

       taupc = taufo * (lppc/lpfo) * sqrt(vfo/vpc)

       !  End of High Energy Transport Stage:
       !  Voltage gradient (V/m) - limit already reached

       phif = phifo

       !  Length of the high energy transport stage (m)

       xhe = (vf - vfo)/phifo

       write(*,*) '                 Injector:'
       write(*,*) '   vi = ',vi
       write(*,*) '  ibi = ',ibi
       write(*,*) ' taui = ',taui
       write(*,*) ' phii = ',phii
       write(*,*) '  lpi = ',lpi
       write(*,*) '                 End of LET stage:'
       write(*,*) '  vfo = ',vfo
       write(*,*) ' ibfo = ',ibfo
       write(*,*) 'taufo = ',taufo
       write(*,*) 'phifo = ',phifo
       write(*,*) ' lpfo = ',lpfo
       write(*,*) '  xle = ',xle
       write(*,*) '                 End of PC stage:'
       write(*,*) '  vpc = ',vpc
       write(*,*) ' ibpc = ',ibpc
       write(*,*) 'taupc = ',taupc
       write(*,*) 'phipc = ',phipc
       write(*,*) ' lppc = ',lppc
       write(*,*) '  xpc = ',xpc
       write(*,*) '                 End of HET stage:'
       write(*,*) '   vf = ',vf
       write(*,*) '  ibf = ',ibf
       write(*,*) ' tauf = ',tauf
       write(*,*) ' phif = ',phif
       write(*,*) '  lpf = ',lpf
       write(*,*) '  xhe = ',xhe

       !  Volt-second requirements and number of cores

       !  Volt-seconds per core (2.4T is field swing of the core
       !  material metglas)

       drcore = 0.8D0
       dlcore = 0.2D0
       vscore = 2.4D0 * drcore * dlcore

       !  Low energy stage

       vsle = taui * vi * log(vfo/vi)
       ncle = 1 + int(vsle/vscore)

       !  Pulse compression stage

       vspc = 2.0D0 * tauf * sqrt(vf) * (sqrt(vpc)-sqrt(vfo))
       ncpc = 1 + int(vspc/vscore)

       !  High energy stage

       drcore = 0.4D0
       dlcore = 0.1D0
       vscore = 2.4D0 * DRCORE * DLCORE

       vshe = 2.0D0 * tauf * vf * (1.0D0 - sqrt(vpc/vf))
       nche = 1 + int(vshe/vscore)

       write(*,*) '                 Number of cores: '
       write(*,*) ' ncle = ',ncle
       write(*,*) ' ncpc = ',ncpc
       write(*,*) ' nche = ',nche

       !  Quadrupole requirements

       !  Effective quadrupole length (m)

       lq = ( emitt * etai * sig0**2 * sqrt(c2*vi) / &
            (sig*(bmax/1.5D0)**2) )**(0.333333D0) * &
            sqrt(2.0D0*aaion*mproton/(qion*echarge))

       write(*,*) '   lq = ',lq

       !  Actual quadrupole length (m)

       write(*,*) '  alq = ',lq/etai

       !  Length of quadrupole focussing fields: low energy stage

       lfocus = etai * vi/phii * (1.0D0 - vi/vfo)
       nqle = 1 + int(lfocus/lq)

       !  Pulse compression + high energy stages

       lfocus = 2.0D0 * etai * sqrt(vi)/phifo * (sqrt(vf) - sqrt(vfo))

       nqpche = 1 + int(lfocus/lq)

       !  Number of quadrupole arrays

       nqarrs = nqle + nqpche

       !  Number of quadrupoles

       nquads = nqarrs * nbeams

       write(*,*) 'nqarrs = ',nqarrs
       write(*,*) 'nquads = ',nquads

       etadrv = 0.28D0

    else

       !  Simple model
       !  ============

       !  gve(k): target gain at edrive = k MegaJoules

       gve(1)  = 25.0D0
       gve(2)  = 44.0D0
       gve(3)  = 62.0D0
       gve(4)  = 76.0D0
       gve(5)  = 87.0D0
       gve(6)  = 97.0D0
       gve(7)  = 107.0D0
       gve(8)  = 115.0D0
       gve(9)  = 125.0D0
       gve(10) = 132.0D0

       !  eve(k): driver efficiency at edrive = k MegaJoules

       eve(1)  = 0.232D0
       eve(2)  = 0.256D0
       eve(3)  = 0.269D0
       eve(4)  = 0.276D0
       eve(5)  = 0.282D0
       eve(6)  = 0.286D0
       eve(7)  = 0.290D0
       eve(8)  = 0.292D0
       eve(9)  = 0.294D0
       eve(10) = 0.296D0

       e = 1.0D-6 * edrive
       ie = int(e)
       de = e - dble(IE)

       !  Assume linear interpolations and extrapolations
       !  Would be better to prevent extrapolation

       if (ie <= 1) then

          gain   = gve(2) - 1.0D-6*(edrive-2.0D6)*(gve(1)-gve(2))
          etadrv = eve(2) - 1.0D-6*(edrive-2.0d6)*(eve(1)-eve(2))

       else if (ie >= 9) then

          gain   = gve(9) + 1.0D-6*(edrive-9.0D6)*(gve(10)-gve(9))
          etadrv = eve(9) + 1.0D-6*(edrive-9.0D6)*(eve(10)-eve(9))

       else

          gain   = gve(ie) + de*(gve(ie+1)-gve(ie))
          etadrv = eve(ie) + de*(eve(ie+1)-eve(ie))

       end if

       !  Ensure sensible values

       gain = max(0.01D0,gain)
       etadrv = max(0.01D0,etadrv)

    end if

  contains

    ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

    function cbeam(etai,bmax,aaion,qion,sigma,sigma0,emitt,vi,eomc2)

      !! Routine to evaluate the beam current coefficient, CI
      !! author: P J Knight, CCFE, Culham Science Centre
      !! etai   : input real : Axial quadrupole packing fraction at injection
      !! bmax   : input real : Maximum field at the superconductor (T)
      !! aaion  : input real : Ion mass (amu)
      !! qion   : input real : Ion charge state
      !! sigma  : input real : Depressed tune (incl. space charge effects) (rad)
      !! sigma0 : input real : Phase advance per lattice period (tune) (rad)
      !! emitt  : input real : Normalised beam emittance (metre-rad)
      !! vi     : input real : Injection voltage (V)
      !! eomc2  : input real : Electron charge / (proton mass * light speed**2)
      !! This routine calculates the beam current coefficient
      !! of a heavy ion driver suitable for inertial fusion energy.
      !! Heavy-ion Driver Design and Scaling, R. Bieri et al.,
      !! Fusion Technology, vol.21 (1992) 1583
      !!       !
      ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

      implicit none

      real(dp) :: cbeam

      !  Arguments

      real(dp), intent(in) :: etai,bmax,aaion,qion,sigma,sigma0, &
           emitt,vi,eomc2

      !  Local variables

      real(dp) :: bbe

      ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

      !  Maximum field at the beam edge

      bbe = bmax/1.5D0

      !  Perform calculation

      cbeam = 2.89D6*(1.0D0-(sigma/sigma0)**2) * &
           ( sigma0**4 * etai**2 * vi * aaion/qion * (emitt/sigma)**2 &
           * bbe**2 )**0.333333D0 &
           * (2.0D0 * qion * eomc2 / aaion)**(5.0D0/6.0D0)

    end function cbeam

    ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

    function betgam(aaion,qion,v)

      !! Routine to calculate the relativistic factor (beta*gamma) for the
      !! heavy ions in the beam driver
      !! author: P J Knight, CCFE, Culham Science Centre
      !! aaion  : input real : Ion mass (amu)
      !! qion   : input real : Ion charge state
      !! v      : input real : Acceleration voltage (V)
      !! This routine calculates the relativistic factor (beta*gamma) for the
      !! heavy ions in a beam driver suitable for inertial fusion energy.
      !! Heavy-ion Driver Design and Scaling, R. Bieri et al.,
      !! Fusion Technology, vol.21 (1992) 1583
      !!       !
      ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

      implicit none

      real(dp) :: betgam

      !  Arguments

      real(dp), intent(in) :: aaion,qion,v

      !  Local variables

      real(dp), parameter :: c2 = 8.98755178737D16

      ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

      betgam = sqrt( 2.0D0*qion*echarge*v / (aaion*mproton*c2) )

    end function betgam

  end subroutine iondrv