ABSTRACT
The firs t ful ly electromagnetic algorithm was devised by 1. M . Dawson in Id (unpubl ished, ca. 1 965 ) . He separated the transverse fields in to left-and right-going components. By choosing Llx = ell t , these components are advanced in t ime simply by shift ing the values over one cel l and adding current contribut ions from particles whose paths intersect the l ight rays. We discuss a variat ion of this Id algori thm as formulated and implemented by Langdon and Dawson ( 1 967) and revived for laser-plasma studies by B. 1 . Cohen, M. A. Mostrom , D. R . Nicholson, and A . B . Langdon ( Cohen et at. , 1 97 5 ) .
