diff --git a/matlab/AUG/aug_requests_mapping.m b/matlab/AUG/aug_requests_mapping.m
index c755d4bac98c407e8cd26c8c3ec9b82b75358416..26360b67e970152a80d3efa24d2488ab970a661b 100644
--- a/matlab/AUG/aug_requests_mapping.m
+++ b/matlab/AUG/aug_requests_mapping.m
@@ -25,7 +25,7 @@ mapping.label = data_request;
 % for AUG, following choices are set so far:
 % method = 'signal' then expression contains the shotfile, diagnostic and if needed the experiment
 %                expression is a cell array
-% method = 'expression', then expression is the expression to return gdat_tmp...
+% method = 'expression', then expression is executed and it should provide the structure gdat_tmp, which fields are copied to gdat_data
 % method = 'switchcase', then there will be a specific case within gdat_aug (usual case when not directly a signal)
 %
 % label is used for plotting
@@ -187,11 +187,12 @@ switch lower(data_request)
   mapping.label = 'li3';
   mapping.method = 'expression';
   mapping.expression = ['params_eff = gdat_data.gdat_params;params_eff.data_request=''li'';' ...
-                    'gdat_tmp=gdat_aug(shot,params_eff);params_eff.data_request=''volume'';r0exp=1.65;gdat_tmp.r0=r0exp;' ...
-                    'gdat_tmp2=gdat_aug(shot,params_eff);ij=find(gdat_tmp2.data==0);gdat_tmp2.data(ij)=NaN;' ...
+                    'gdat_tmp=gdat_aug(shot,params_eff);r0exp=1.65;gdat_tmp.r0=r0exp;' ...
+                    'params_eff.data_request=''volume'';' ...
+                    'gdat_vol=gdat_aug(shot,params_eff);ij=find(gdat_vol.data==0);gdat_vol.data(ij)=NaN;' ...
                     'params_eff.data_request=[{''FPG''},{''Circumf''}];' ...
-                    'gdat_tmp3=gdat_aug(shot,params_eff);ij=find(gdat_tmp3.data==0);gdat_tmp3.data(ij)=NaN;' ...
-                    'gdat_tmp.conversion_factor_liefit_li3=gdat_tmp.r0./2.*gdat_tmp3.data.^2./gdat_tmp2.data;' ...
+                    'gdat_pol_length=gdat_aug(shot,params_eff);ij=find(gdat_pol_length.data==0);gdat_pol_length.data(ij)=NaN;' ...
+                    'gdat_tmp.conversion_factor_liefit_li3=gdat_tmp.r0./2.*gdat_pol_length.data.^2./gdat_vol.data;' ...
 		    'gdat_tmp.data = gdat_tmp.data./gdat_tmp.conversion_factor_liefit_li3;'];
  case 'mhd'
   mapping.timedim = 1;