Variable averaging radius for space-charge density.


This option is concerned with the averaging radius for calculating the space-charge density that is sent to the user-supplied routine in the stochastics option.  In this option the averaging radius can be changed during ray tracing (that is, trajectory integration).  It is accessed by databuilder/sources of rays/advanced options/.


For example you might want the averaging radius to be 0.1 most of the time but to be reduced to 0.01 for the part of the trajectory that is between z = .95 and 1.05. You might also want to specify a second region of changed radius, eg to 0.02 between z = 1.5 and 1.6.


The number of regions and their limiting z values are those specified for the option to change the step length.  See the note on changing the maximum step length for information on how regions can be set up in which the maximum step length can be changed.


It is expected that when dlmax is reduced in a region then the averaging radius would also be reduced in the same region. But this might not always be the case.  Therefore it is possible to ignore a region by giving it a negative value of dlmax or tube radius.


If more than one region is specified then the program treats the nth region after the (n-1)th region, which means that the later regions can be superimposed inside the earlier regions.


Return to general note ray space charges


Return to note on changing the maximum step length.


Return to general note on stochastic option