PRO plot_va
  
;reads Alfven velocity from Hall-MHD simulation on the x-y-simulation grid
  restore,'Figure_11a_va_color.sav'
  ;.sav includes, fa,xf,yf,time,nl2,nxf,nrot,pos1,pos2,xpos,ypos

;simulation time in the units of Alfven time
;loads color table
loadct,file='colortab.priv', 45
xtitl='y'
ytitl='-x'
  
        !P.POSITION=pos1
        IMAGE_C, rotate(fa,nrot)
        bmax=max(fa) & bmin=min(fa) &  bav=0.5*(bmax+bmin)
        if ( (bmax-bmin) lt 0.000001) then begin
          bmax=bmax+0.0000005 & bmin=bmin-0.0000005 & endif
        del=(bmax-bmin)/(nl2-1.)
        if (bmax*bmin ge 0.) or (abs(bmin) lt 0.2*abs(bmax)) then $
          cb=bav else cb=0.
        contour,fa,xf,yf,levels=findgen(nl2)*del+bmin,$
        c_linestyle=1,$
        title=titl,xstyle=1,ystyle=1,$
        xtitle=xtitl, /noerase
	xyouts,charsize=1.1,xpos(0),ypos(8),'time = '+string(time,'(f6.2)') 
	xyouts,charsize=1.0,-xpos(0)-2.5,0., ytitl


	!P.POSITION=pos2
	fmax=bmax & fmin=bmin
	ddel=(fmax-fmin) & del=ddel/float(nxf-1)
	ctab=findgen(nxf) & ctab=del*ctab+fmin & cbary=findgen(2,nxf)
	cbary(0,*)=ctab(*) & cbary(1,*)=ctab(*)
        IMAGE_C, cbary
	contour,cbary,[0,1],ctab,levels=findgen(nl1)*ddel/(nl1-1.)+fmin,$
	xstyle=1,ystyle=1,c_linestyle=1,xrange=[0,1],yrange=[fmin,fmax],$
        xtickname=names,xticks=1,ytickformat='(f5.2)',/noerase
        


        
return
end