[cig-commits] r5820 - geodyn/3D/MAG/trunk/src

[wei at geodynamics.org]

Author: wei
Date: 2007-01-17 21:12:55 -0800 (Wed, 17 Jan 2007)
New Revision: 5820

Added:
   geodyn/3D/MAG/trunk/src/getgauss.f
Modified:
   geodyn/3D/MAG/trunk/src/par.Revmv
   geodyn/3D/MAG/trunk/src/par.bnch1mv
   geodyn/3D/MAG/trunk/src/param.f
Log:
Add a subroutine to convert between the Gauss coefficients and spherical harmonic coefficients

Added: geodyn/3D/MAG/trunk/src/getgauss.f
===================================================================
--- geodyn/3D/MAG/trunk/src/getgauss.f	2007-01-18 01:04:54 UTC (rev 5819)
+++ geodyn/3D/MAG/trunk/src/getgauss.f	2007-01-18 05:12:55 UTC (rev 5820)
@@ -0,0 +1,82 @@
+	subroutine getgauss(l,m,alm,blm,glm,hlm,id)
+	
+c	this subroutine converts between Gauss coefficients (glm, hlm)
+c      	and the spherical harmonic coefficients (alm,blm)
+c	of the magnetic potential at harmonic degree l 
+c	and order m used by the numerical dynamo model MAG. 
+c 
+c	Inputs:
+c		l,m: integer spherical harmonic degree and order;
+c
+c		id: transformation direction:
+c			id = 1 converts (alm,blm) to (glm,hlm)
+c			id =-1 converts (glm,hlm) to (alm,blm)             
+c
+c		alm,blm: dimensionless spherical harmonic coefficients 
+c			of the radial magnetic field potential on the
+c			outer boundary of the dynamo model. alm is the
+c			coefficient of the real (cosine) part and blm 
+c			is for the imaginary (sine) part.
+c
+c		glm,hlm: Gauss coefficients in nanotessla	(nT).	
+c                        glm multiplies with cos(m*phi)
+c                        hlm multiplies with sin(m*phi)
+c		
+c	The calculation uses SI units and nominal Earth values for
+c	surface and core radii. The 
+c	conversion from dimensionless (alm,blm) to (glm,hlm) in
+c	nT uses Earth values for density, rotation, electrical 
+c	conductivity, and uses the depth of the outer core as the
+c	length scale.
+
+		if (l .le. 0 .or. m .lt. 0 .or. m .gt. l) then
+			write(6,'(''bad l or m in getgauss'')')
+			return
+		endif	 
+c
+c	constants
+c
+		pi=4.*atan(1.)
+		pi4inv=1./(4.*pi)
+		anano=1.0e+09
+c
+c	nominal Earth parameters
+c
+		sigma=6.0e+05     ! Core electrical conductivity in S/m
+		rho=11.e+03       ! Core mean density in kg m^{-3}
+		omega=7.2924e-05  ! Rotation angular frequency
+		escale=sqrt(rho*omega/sigma)  ! "Elsasser number" scaling	
+		re=6.371e+06      ! Earth radius in m
+		rc=3.485e+06      ! Core radius in m
+		ri=1.215e+06      ! Inner core radius in m
+		cdepth=rc-ri      ! Depth of outer core
+		rcre=rc/re        ! core/surface radius ratio
+		rcsqinv=(cdepth/rc)**2  ! dim-less inverse squared core radius
+c     				
+c	harmonic factors	
+c
+		fl=float(l)
+		flp2=fl + 2.
+		fl2p1=(2.*fl) + 1.
+		fm=float(m)
+		fact=sqrt(fl2p1*pi4inv)
+		fact1=((-1.)**fm)*fl*fact
+                if(m.gt.0) fact1=fact1*sqrt(2.)
+		fact2=rcsqinv*(rcre**flp2)
+c
+c	define MAG harmonic-Gauss harmonic conversion factors 
+c	conalm,conblm
+c
+		conalm=fact1
+		conblm=-fact1
+c
+		if (id .gt. 0) then  ! form Gauss coeffs in nT	
+			glm=anano*escale*fact2*conalm*alm
+			hlm=anano*escale*fact2*conblm*blm
+		        return
+		else ! form dimensionless fully normalized potential coeffs
+			alm=glm/(anano*escale*fact2*conalm)
+			blm=hlm/(anano*escale*fact2*conblm)
+		return
+		endif
+	end

Modified: geodyn/3D/MAG/trunk/src/par.Revmv
===================================================================
--- geodyn/3D/MAG/trunk/src/par.Revmv	2007-01-18 01:04:54 UTC (rev 5819)
+++ geodyn/3D/MAG/trunk/src/par.Revmv	2007-01-18 05:12:55 UTC (rev 5820)
@@ -30,7 +30,7 @@
  ktopv=2,
  kbotv=2,
  difamp=0,
- imovopt=001,
+ imovopt=111,
  tmovstart=2.0,
  tmovstep=2.E-3,
  iframes=100,

Modified: geodyn/3D/MAG/trunk/src/par.bnch1mv
===================================================================
--- geodyn/3D/MAG/trunk/src/par.bnch1mv	2007-01-18 01:04:54 UTC (rev 5819)
+++ geodyn/3D/MAG/trunk/src/par.bnch1mv	2007-01-18 05:12:55 UTC (rev 5820)
@@ -30,7 +30,7 @@
  ktopv=2,
  kbotv=2,
  difamp=0,
- imovopt=001,
+ imovopt=111,
  tmovstart=2.0,
  tmovstep=2.E-3,
  iframes=100,

Modified: geodyn/3D/MAG/trunk/src/param.f
===================================================================
--- geodyn/3D/MAG/trunk/src/param.f	2007-01-18 01:04:54 UTC (rev 5819)
+++ geodyn/3D/MAG/trunk/src/param.f	2007-01-18 05:12:55 UTC (rev 5820)
@@ -1 +1 @@
-link param32s4.f
\ No newline at end of file
+link param32s1.f
\ No newline at end of file