cdefByMagAndE.f File Reference

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Modules
module	modbefield

Functions/Subroutines
subroutine	cgetefield (aTrack)
subroutine	cdefbymagande (aTrack, leng, dispmr, dispmd, newmom)
real(8) function, dimension(nv)	fbedeflection (t, u, nv)

Variables
real(8), dimension(3), save	bfld
real(8), dimension(3), save	efld
real(8), save	eval =0.29979
real(8), save	ptclmass
real(8), save	ptclz

Function/Subroutine Documentation

cdefbymagande()

subroutine cdefbymagande	(	type(track)	aTrack,
		real(8), intent(in)	leng,
		type(coord)	dispmr,
		type(coord)	dispmd,
		real(8), dimension(3), intent(out)	newmom
	)

Definition at line 40 of file cdefByMagAndE.f.

References modbefield::bfld, c, cgetefield(), modbefield::ptclmass, and modbefield::ptclz.

Referenced by cmagdef().

      use modbefield
      use modefield
      implicit none
#include "Zglobalc.h"
#include "Ztrack.h"
#include "Ztrackv.h"
#include "Zmass.h"

      type(track)::atrack ! input. current  track
      real(8),intent(in):: leng !  moved length in m
      type(coord)::dispmr !  output displacement 
      type(coord)::dispmd !  output new direction cos
      real(8),intent(out):: newmom(3) ! chnaged momentum

      integer,parameter:: nsim=6
      integer,parameter::nstep=1  ! if 2, accuracy may increse
      real(8):: t(0:nstep), u(6,0:nstep)
!xxxxxxxxxx next equivalence does not work (ifort)
!      real(8):: r(3,0:nstep), p(3,0:nstep)
!      equivalence( r(1,0), u(1,0) )
!      equivalence( p(1,0), u(4,0) )
      real(8):: dt  ! time step in s. 
      real(8),external:: fbedeflection ! function to give f of u'=f
         ! where  u=(r,p), u'=(v, Ze(E+VxB)
      real(8):: p2, e, gamma, bt
      integer::n
!!!!!!!!!!
      real(8),save:: pos(3)=(/0.,0.,0./)
!!!!!!!!!!!!!!!

!      here we assume B is given by Mag (const).
      bfld(:) =(/mag%x, mag%y, mag%z/)
!      Bfld(:) =(/0.3d-4, 0.d0, 0.d0/)  ! test

      call cgetefield(atrack)  ! ans is in Efld

      u(1:3, 0) = 0.   ! r=0 we need only dr 
!      u(1:3, 0) =  aTrack.pos.xyz.r(1:3)

      u(4:6, 0) = atrack%p%fm%p(1:3)  ! px,py,pz in GeV/c
      ptclz = atrack%p%charge
      ptclmass =atrack%p%mass
      e = atrack%p%fm%p(4)
      gamma = e/ptclmass
      bt = sqrt( (gamma-1)*(gamma+1))/gamma
      dt = leng/c/bt
      forall(n=0:nstep) t(n) = n*dt
      call ksrunge_kutta4(t, u,  nstep, nsim, dt,
     *     fbedeflection)
      dispmr%r(:) = u(1:3,nstep) - u(1:3,0)
!!!!!!!!!!
!      pos(:) = pos(:) + dispmr.r(:)
!      write(*,'(a,1p, 3g14.4)') 'pos ', pos(:)
!      write(*,'(a,1p, 3g14.4)') 'pos2 ',u(1:3,nstep)
!!!!!!!!!!!!!!!
      p2 =dot_product( u(4:6,nstep), u(4:6,nstep) )
      if( p2 > 0.) then
         dispmd%r(:) = u(4:6,nstep)/ sqrt( p2) 
      else
         dispmd%r(:) = (/0.,0.,1./)
      endif
      newmom(:) = u(4:6,nstep)

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cgetefield()

subroutine cgetefield

(

type(track)

aTrack

)

Definition at line 11 of file cdefByMagAndE.f.

References modefield::cefield0(), cmyefield(), modbefield::efld, and modefield::howefield.

Referenced by cdefbymagande(), and cmaxefefflen().

      use modbefield
      use modefield
      implicit none
#include "Zglobalc.h"
#include "Ztrack.h"
#include "Ztrackv.h"
#include "Zmass.h"

      type(track)::atrack ! input. current  track
      if(howefield == 1 ) then
         call cefield0(atrack, efld)
      else
#if defined (MYEFIELD) 
!        not simple Efield; user must define next
         call cmyefield(atrack, efld)
#else
         write(0,*) "HowEfield=",howefield," invalid"
         write(0,*) "You must define MYEFIELD  in Zcondc%h"
         write(0,*)
     *    "and prepare cmyEfield subroutine in your apps.",
     *    "Interface is cmyEfield(aTrack,Efout); see",
     *    "manual or cEfield0 in Cosmos/Module"
         stop
#endif
      endif

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fbedeflection()

real(8) function, dimension(nv) fbedeflection	(	real(8), intent(in)	t,
		real(8), dimension(nv), intent(in)	u,
		integer, intent(in)	nv
	)

Definition at line 105 of file cdefByMagAndE.f.

References modbefield::bfld, c, modbefield::efld, modbefield::eval, modbefield::ptclmass, and modbefield::ptclz.

!     charged ptcl motion in E and B
!     dp/dt =Ze(E+ VxB)=ZeE+Ze(VyBz-VzBy, VzBx-BxBz, VxBy-VyBx)
!     u=(x,y,z, px,py,pz) u'=(v, force)
!     v = pc/E
      use modbefield
      implicit none
#include "Zglobalc.h"
      integer,intent(in):: nv   ! # of variable; simultaneous eq
      real(8),intent(in):: t  ! given time
      real(8),intent(in):: u(nv)  ! value of u for du/dt=f
      real(8)::ans(nv)  !  f
!               f(1:3) = dr/dt = beta c = pc/E
!               f(4;6) = dp/dt = Ze(E+vxB) 
      real(8)::p2, e
      real(8)::vp(3), temp(3)
      vp(:) = u(4:6)  ! p
      p2= dot_product( vp, vp)
      e = sqrt(ptclmass**2 + p2)
!      gamma = E/m
!      beta = sqrt( (gamma-1)*(gamma+1))/gamma
      ans(1:3) = vp(:)*c/e  ! pc/E = c*beta => v
      call kvec_prod3(ans(1:3), bfld, temp(1:3))  ! vxB
      ans(4:6) = ptclz*eval*(temp(1:3) + efld(1:3))