Your are looking for `assign()`.

    for(i in 1:3){
      assign(paste("a", i, sep = ""), i)	
    }

gives

    > ls()
    [1] "a1"          "a2"          "a3" 

and

    > a1
    [1] 1
    > a2
    [1] 2
    > a3
    [1] 3