This section enables the computation of longitudinal and transverse wake potentials from data that were computed by gd1. These data are only recorded by gd1 when you did specify a charge in the section -lcharge of gd1.
gd1 computes the integral of the 
component along the outermost
paths where a beam can travel and stores the result in the database.
Since from these data the longitudinal and transverse wakepotentials everywhere
in the beam pipe can be computed, you can specify an unlimited number of
positions (x,y) where you are interested in the wakepotentials.
The (x,y) position of the exciting charge cannot be changed afterwards,
though.
############################################################################## # Flags: nomenu, noprompt, nomessage, # ############################################################################## # section -wakes # ############################################################################## # set = 0 -- What dataset (windowwake only) # # watq = yes -- Process all wakes at positions of Zeile-charges # # awtatq = yes -- Use the average of the two nearest transverse wakes # # -- as the transverse wakes at the positions of charges # # impedances= no -- Compute impedances. # # window = yes -- Apply hann-window when computing impedances. # # fhigh = undefined -- fhigh of impedances. # # uselu = yes -- Use Sparse LU-Factorisation. # # uselowpass= no -- Use lowpass filtering. # # usehighpass= no -- Use highpass filtering. # # showchargemax= no -- Show value of charge maximum. # # centerbunch= yes -- Shift data. Bunch center will be at s=0. # # xyref = ( 0.0, 0.0) -- refpoint for ??atxy-data # # usexyref = no -- use refpoint? # # clear -- clears all the "w*at*" values. # # watxy = ( undefined, undefined) -- want wz(xi,yi,s), i= 1 # # wxatxy= ( undefined, undefined) -- want wx(xi,yi,s), i= 1 # # wyatxy= ( undefined, undefined) -- want wy(xi,yi,s), i= 1 # # watsi = undefined -- want w(x,y,si), i= 1 # # watxi = undefined -- want w(xi,y,s), i= 1 # # liny= 20 -- number of Zeiles in y-direction. # # watyi = undefined -- want w(x,yi,s), i= 1 # # linx= 20 -- number of Zeiles in x-direction. # # wxatxi= undefined -- want wx(xi,y,s), i= 1 # # wxatyi= undefined -- want wx(x,yi,s), i= 1 # # wyatxi= undefined -- want wy(xi,y,s), i= 1 # # wyatyi= undefined -- want wy(x,yi,s), i= 1 # # istrides= 3 -- distance of s-points of the plots # # -- in units of "ds". # # slow = 0.0 -- lowest s-value to consider # # shigh= undefined -- highest s-value to consider # # watsfiles = -none- # xlowwats = -1.0e+30 # # xhighwats= 1.0e+30 # # ylowwats = -1.0e+30 # # yhighwats= 1.0e+30 # # frequency= undefined ( @ufrequency : undefined ) # # ( @zxesrf: undefined ) # # ( @zxesrf: undefined ) # # ( @zxesrf: undefined ) # # ( @xloss : undefined ) [VAs] # # ( @yloss : undefined ) [VAs] # # ( @zloss : undefined ) [VAs] # # ( @charge: undefined ) [As] # ############################################################################## # plotopts = -geometry 690x560+10+10 # # showtext = yes -- (yes | no) # # onlyplotfiles= no -- (yes | no) # ############################################################################## # return, help, end, clear, doit # ##############################################################################
-windowwake, one can compute
in a single run the wakepotentials of different numbers of periodic sections
of a periodic geometry. The different results are call sets. The number of
the set to analyse is specified.
yes 
no ![$]$](img95.gif){kind=small}
yes 
no ![$]$](img98.gif){kind=small}
If awtatq= yes, gd1.pp computes the transverse wakepotentials at the two positions between the grid planes that are nearest to the position of the exciting charge. The average of the two potentials are then assumed to be the transverse wakepotential at the position of the charge.
yes 
no ![$]$](img101.gif){kind=small}
yes 
no ![$]$](img104.gif){kind=small}
yes 
no ![$]$](img107.gif){kind=small}
uselu=no, the linear equations are solved with
an iterative scheme, which requires less memory, but much more time.
yes 
no ![$]$](img110.gif){kind=small}
yes 
no ![$]$](img113.gif){kind=small}
usexyref=yes, the transverse wakepotentials at (XREF,YREF)
are computed, and the other transverse wakepotentials are
plotted as eg.
.
You can specify an unlimited number of (x,y)-positions where you want to know the longitudinal or transverse wakepotentials.
You can specify an unlimited number of s-positions where you want to know the longitudinal or transverse wakepotentials.
You can specify an unlimited number of y- or y-positions where you want to know the longitudinal wakepotentials.
If you specify wxatxi= Xi, the transverse wakepotential in x-direction will be plotted in the y-s plane at the x-coordinate between meshplanes nearest to Xi.
If you specify wxatyi= Yi, the transverse wakepotential in x-direction will be plotted in the x-s plane at the y-coordinate between meshplanes nearest to Yi.
If you specify wyatxi= Xi, the transverse wakepotential in y-direction will be plotted in the y-s plane at the x-coordinate between meshplanes nearest to Xi.
If you specify wyatyi= Yi, the transverse wakepotential in y-direction will be plotted in the x-s plane at the y-coordinate between meshplanes nearest to Yi.
You can specify an unlimited number of y- or y-positions where you want to know the transverse wakepotentials.
plotopts= ANY STRING CONTAING OPTIONS FOR THE PLOT-PROGRAMS:
showtext= [yes|no]:
onlyplotfiles= [yes|no]:
@zloss, @xloss, @yloss after
a wake-potential computation.
-wake
watxi= 1e-3
watxi= 2e-3